[CP][web] Make 'Noto Color Emoji' opt-in (#40990)

[CaseyHillers]

[web] Make 'Noto Color Emoji' opt-in

b/277330347 - This incurred a large 24 MB size increase for web projects that is blocking customer releases.

Pre-launch Checklist

• I read the [Contributor Guide] and followed the process outlined there for submitting PRs.
• I read the [Tree Hygiene] wiki page, which explains my responsibilities.
• I read and followed the [Flutter Style Guide] and the [C++, Objective-C, Java style guides].
• I listed at least one issue that this PR fixes in the description above.
• I added new tests to check the change I am making or feature I am adding, or Hixie said the PR is test-exempt. See [testing the engine] for instructions on writing and running engine tests.
• I updated/added relevant documentation (doc comments with ///).
• I signed the [CLA].
• All existing and new tests are passing.

[flutter-dashboard]

This pull request was opened from and to a release candidate branch. This should only be done as part of the official Flutter release process. If you are attempting to make a regular contribution to the Flutter project, please close this PR and follow the instructions at Tree Hygiene for detailed instructions on contributing to Flutter.

Reviewers: Use caution before merging pull requests to release branches. Ensure the proper procedure has been followed.

[XilaiZhang]

Umm I think flutter-3.10-candidate.1 is tied to the current roll at commit e749db6

[CaseyHillers]

Umm I think flutter-3.10-candidate.1 is tied to the current roll at commit e749db6

Exactly :-)

Your roll will land, and I'll CP in afterwards. Since this is going to take several hours to run through LUCI, I'm starting now.