Add support for AVC in HEIF mime types (backport #3085)

[mergify]

https://www.iana.org/assignments/media-types/image/avci
https://www.iana.org/assignments/media-types/image/avcs

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This is an automatic backport of pull request #3085 done by Mergify.

[mergify]

Cherry-pick of 1f97a0a has failed:

On branch mergify/bp/0.28.x/pr-3085
Your branch is up to date with 'origin/0.28.x'.

You are currently cherry-picking commit 1f97a0a7e.
  (fix conflicts and run "git cherry-pick --continue")
  (use "git cherry-pick --skip" to skip this patch)
  (use "git cherry-pick --abort" to cancel the cherry-pick operation)

Unmerged paths:
  (use "git add <file>..." to mark resolution)
	both modified:   src/bmffimage.cpp

no changes added to commit (use "git add" and/or "git commit -a")

To fix up this pull request, you can check it out locally. See documentation: https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/reviewing-changes-in-pull-requests/checking-out-pull-requests-locally