Update generate_gradle_lockfiles script to represent newer templates, and run it on dev/

[gmackall]

Upgrades agp versions and lockfiles for dev/. Also changes the lockfile generation script to represent the newer form of the settings.gradle template, and therefore also propagates these changes.

Potentially related to #134419, but worth doing anyways. (not actually related)

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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[gmackall]

Closing in favor of #137190

[gmackall]

Reopening this because #137198 was reverted (there was nothing wrong with it, it was mistakenly identified as the source of tree-redness). I still think we should consider whether these lockfiles should exist, but in the meantime we should make sure the script uses the correct version of the settings.gradle file.