Add youtube shorts url rule and fix youtube video embedding

[twinkarma]

• [x] Support youtube shorts url
• [x] Fixed embedding for normal youtube videos
• [x] Show "Content does not support embedding" message in place for youtube shorts,
  • Translations are in this PR https://github.com/AFP-Medialab/InVID-Translations/pull/86
• Services linked by the assistant
  • [ ] Video analysis - We cannot extract an video ID from the submitted URL. Please note also that Facebook does not allow us to process videos from Users or Groups
  • [x] Keyframe - Works
  • [ ] Thumbnail - Runs but no thumbnail generated
  • [ ] Video rights - Unknown error occurred

[twinkarma]

This is what embedding looks like with youtube shorts. Should we put some placeholder graphics in?

[twinkarma]

• Add message to effect of "Youtube shorts only partially supported"
• Simplify text about youtube shorts video embeddeding

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Thanks for the review @rosannamilner !