Update Emoji digests and assets with latest from Gemojione v3.3.0

What does this MR do?

• Update emoji digests and assets with latest from Gemojione
  • Removes comma from cartwheel_tone4, https://gitlab.com/gitlab-org/gitlab-ce/issues/32634
  • Adds gay_pride_flag (rainbow_flag)
  • Adds speech_left (left_speech_bubble)
  • Updates mrs_clause image
• Add unicode emoji check for the rainbow_flag because it isn't well supported
• Add some basic docs around emojis
• Add cache busting GL_EMOJI_VERSION to regenerate our unicode support map when our logic changes
• Consolidate task to generate aliases.json into the rake file, bundle exec rake gemojione:aliases

Are there points in the code the reviewer needs to double check?

• Look at GFM autocomplete
• Look at the Awards menu
  • Gemojione considers gay_pride_flag in the extras category instead of flags. Should we re-categorize it for our UI? Yes (from UX)!

Why was this MR needed?

The Gemojione dependency was updated v3.3.0 but the new emoji changes weren't reflected in the UI.

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• Documentation created/updated
• Tests added for this feature/bug
• Review
  • Has been reviewed by UX
  • Has been reviewed by Frontend
  • Has been reviewed by Backend
  • Has been reviewed by Database
• Conform by the merge request performance guides
• Conform by the style guides
• Squashed related commits together
• Internationalization required/considered

What are the relevant issue numbers?

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/32634

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cc @connorshea