[Android] Update timeline for landed Intent security work

[camsim99]

Two Intent security changes (https://docs.flutter.dev/release/breaking-changes/stricter-android-entrypoint-intent-verification, https://docs.flutter.dev/release/breaking-changes/restrict-android-engine-flags-release-mode) will be part of the upcoming beta/stable release so updating the timeline!

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[gemini-code-assist]

Code Review

This pull request updates the release timeline details for two Android breaking changes documentation files. The feedback highlights that removing the <br> HTML tags from the timeline section will cause the lines to render on a single line in standard Markdown, and suggests retaining the tags to preserve proper formatting.

[flutter-website-bot]

Staged preview of the updated docs.flutter.dev site (updated for commit bfe1887):

https://flutter-docs-prod--docs-pr13978-intent-landed-aau7c47u.web.app

[flutter-website-bot]

Staged preview of the updated flutter.dev site (updated for commit ef67074):

https://flutter-dev-230821--www-pr13978-intent-landed-11gl4oii.web.app

[jesskuras]

Thanks for updating these, @camsim99! Per our breaking changes template, we keep In stable release set to Not yet until the stable release is actually published (at which point we update both the stable version and the breaking changes index page). Once these two suggestions are applied, this is good to merge!

[camsim99]

Gotcha, thanks for the clarification!