Reland "Make Flutter version information accessible at runtime (#140783)" - #163761

Reverts #163753
Relands #140783

Original PR description below

This makes various Flutter version information available at runtime. It's basically the same as executing flutter --version. This is especially useful for tools like Crashlytics or Sentry (see for example getsentry/sentry-dart#416).

Usage example:

FlutterVersion.version;           // 3.16.5
FlutterVersion.channel;           // stable
FlutterVersion.gitUrl;            // https://github.com/flutter/flutter.git
FlutterVersion.frameworkRevision; // 78666c8dc5
FlutterVersion.engineRevision;    // 3f3e560236
FlutterVersion.dartVersion;       // 3.2.3

This approach has prior art as seen in #134179.

Fixes #61814

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, including Features we expect every widget to implement.
• I signed the CLA.
• I listed at least one issue that this PR fixes in the description above.
• I updated/added relevant documentation (doc comments with ///).
• I added new tests to check the change I am making, or this PR is test-exempt.
• All existing and new tests are passing.

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