Backport of "h265parse: Fix framerate handling" into 1.20

Backport of !4259 (merged) "h265parse: Fix framerate handling".

Todo:

• Needs manual intervention, cherry-picking failed!
• push gst-integration-testsuites addition to 1.20 branch
• then and add medias git submodule bump

Commits:

• 49106eab h265parse: Don't override upstream framerate
• 77cda4b6 h265parse: Rename parsed_framerate to framerate_from_caps
• 43e4f3a7 h265parse: Fix to check returned value (bonus commit)
• xxxxxxxx medias: Bump the medias commit
• tooks commits from 1.22 backport in !4352 (merged)