[extractor/opencast] Add ltitools interface to OpencastPlaylistIE and fix Tests
diff --git a/yt_dlp/extractor/opencast.py b/yt_dlp/extractor/opencast.py
index fa46757f7b6..235ca341c48 100644
--- a/yt_dlp/extractor/opencast.py
+++ b/yt_dlp/extractor/opencast.py
@@ -105,10 +105,9 @@ def _parse_mediapackage(self, video):
 
 
 class OpencastIE(OpencastBaseIE):
-    _VALID_URL = r'''(?x)
-                    https?://(?P<host>%s)/paella/ui/watch.html\?.*?
-                    id=(?P<id>%s)
-                    ''' % (OpencastBaseIE._INSTANCES_RE, OpencastBaseIE._UUID_RE)
+    _VALID_URL = rf'''(?x)
+        https?://(?P<host>{OpencastBaseIE._INSTANCES_RE})/paella/ui/watch\.html\?
+        (?:[^#]+&)?id=(?P<id>{OpencastBaseIE._UUID_RE})'''
 
     _API_BASE = 'https://%s/search/episode.json?id=%s'
 
@@ -123,6 +122,9 @@ class OpencastIE(OpencastBaseIE):
                 'thumbnail': r're:^https?://.*\.jpg$',
                 'timestamp': 1606208400,
                 'upload_date': '20201124',
+                'season_id': 'cf68a4a1-36b1-4a53-a6ba-61af5705a0d0',
+                'series': 'Kryptographie - WiSe 15/16',
+                'creator': 'Alexander May',
             },
         }
     ]
@@ -134,10 +136,11 @@ def _real_extract(self, url):
 
 
 class OpencastPlaylistIE(OpencastBaseIE):
-    _VALID_URL = r'''(?x)
-                            https?://(?P<host>%s)/engage/ui/index.html\?.*?
-                            epFrom=(?P<id>%s)
-                    ''' % (OpencastBaseIE._INSTANCES_RE, OpencastBaseIE._UUID_RE)
+    _VALID_URL = rf'''(?x)
+        https?://(?P<host>{OpencastBaseIE._INSTANCES_RE})(?:
+            /engage/ui/index\.html\?(?:[^#]+&)?epFrom=|
+            /ltitools/index\.html\?(?:[^#]+&)?series=
+        )(?P<id>{OpencastBaseIE._UUID_RE})'''
 
     _API_BASE = 'https://%s/search/episode.json?sid=%s'
 
@@ -148,15 +151,23 @@ class OpencastPlaylistIE(OpencastBaseIE):
                 'id': 'cf68a4a1-36b1-4a53-a6ba-61af5705a0d0',
                 'title': 'Kryptographie - WiSe 15/16',
             },
-            'playlist_mincount': 28,
+            'playlist_mincount': 29,
         },
         {
-            'url': 'https://oc-video.ruhr-uni-bochum.de/engage/ui/index.html?e=1&p=1&epFrom=b1a54262-3684-403f-9731-8e77c3766f9a',
+            'url': 'https://oc-video1.ruhr-uni-bochum.de/ltitools/index.html?subtool=series&series=cf68a4a1-36b1-4a53-a6ba-61af5705a0d0&lng=de',
             'info_dict': {
-                'id': 'b1a54262-3684-403f-9731-8e77c3766f9a',
-                'title': 'inSTUDIES-Social movements and prefigurative politics in a global perspective',
+                'id': 'cf68a4a1-36b1-4a53-a6ba-61af5705a0d0',
+                'title': 'Kryptographie - WiSe 15/16',
+            },
+            'playlist_mincount': 29,
+        },
+        {
+            'url': 'https://electures.uni-muenster.de/engage/ui/index.html?e=1&p=1&epFrom=39391d10-a711-4d23-b21d-afd2ed7d758c',
+            'info_dict': {
+                'id': '39391d10-a711-4d23-b21d-afd2ed7d758c',
+                'title': '021670 Theologische Themen bei Hans Blumenberg WiSe 2017/18',
             },
-            'playlist_mincount': 6,
+            'playlist_mincount': 13,
         },
     ]
 

### Description

I'm the original author of the Opencast Extractor (bwildenhain then took care of it further so that it would be merged into yt-dlp. Thanks again for that), and I want to make an update to the extractor.  Opencast now has a new "interface" to access playlists, and that is now used more often than the old one. For that reason I extended the valid URLs of the OpencastPlaylist Extractor

Also I fixed the Tests. oc-video.ruhr-uni-bochum.de seems to be down currently so I replaced it with an other example. I also added the missing keys to the first test.

### Before submitting a *pull request* make sure you have:
- [x] At least skimmed through [contributing guidelines](https://github.com/yt-dlp/yt-dlp/blob/master/CONTRIBUTING.md#developer-instructions) including [yt-dlp coding conventions](https://github.com/yt-dlp/yt-dlp/blob/master/CONTRIBUTING.md#yt-dlp-coding-conventions)
- [x] [Searched](https://github.com/yt-dlp/yt-dlp/search?q=is%3Apr&type=Issues) the bugtracker for similar pull requests
- [x] Checked the code with [flake8](https://pypi.python.org/pypi/flake8) and [ran relevant tests](https://github.com/yt-dlp/yt-dlp/blob/master/CONTRIBUTING.md#developer-instructions)

### In order to be accepted and merged into yt-dlp each piece of code must be in public domain or released under [Unlicense](http://unlicense.org/). Check all of the following options that apply:
- [x] I am the original author of this code and I am willing to release it under [Unlicense](http://unlicense.org/)
- [ ] I am not the original author of this code but it is in public domain or released under [Unlicense](http://unlicense.org/) (provide reliable evidence)

### What is the purpose of your *pull request*?
- [x] Fix or improvement to an extractor (Make sure to add/update tests)
- [ ] New extractor ([Piracy websites will not be accepted](https://github.com/yt-dlp/yt-dlp/blob/master/CONTRIBUTING.md#is-the-website-primarily-used-for-piracy))
- [ ] Core bug fix/improvement
- [ ] New feature (It is strongly [recommended to open an issue first](https://github.com/yt-dlp/yt-dlp/blob/master/CONTRIBUTING.md#adding-new-feature-or-making-overarching-changes))

</details>
