[tool] Build all_packages command against Flutter Android SDK version to match example app compileSdk constraints

[jmagman]

A few dependency bumps are failing due to the all_packages test targeting a lower version of Android SDK than the example apps. Instead of hardcoding an SDK version which needs to be updated manually (https://github.com/flutter/packages/pull/7891/files#r1815169527), instead use flutter.compileSdkVersion, similar to #3847.

Unblocks attempts to increase dependencies versions that require SDK 35 or higher
#7985

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[jmagman]

 │ [!] Using compileSdk 35 requires Android Gradle Plugin (AGP) 8.1.0 or higher.                    

[jmagman]

packages/.ci/legacy_project/all_packages/android/gradle/wrapper/gradle-wrapper.properties

Line 6 in 864e6be

distributionUrl=https\://services.gradle.org/distributions/gradle-7.0.2-all.zip

Bump like #6742

[jmagman]

Error now is that the legacy variant is using a lower version of AGP and needs 8.1

[!] Using compileSdk 35 requires Android Gradle Plugin (AGP) 8.1.0 or higher. │
│ Please upgrade to a newer AGP version. The version of AGP that your project uses is likely │
│ defined in: │
│ /b/s/w/ir/x/w/packages/legacy/all_packages/android/settings.gradle, │
│ in the 'plugins' closure (by the number following "com.android.application"). │
│ Alternatively, if your project was created with an older version of the templates, it is likely │
│ in the buildscript.dependencies closure of the top-level build.gradle: │
│ /b/s/w/ir/x/w/packages/legacy/all_packages/android/build.gradle, │
│ as the number following "com.android.tools.build:gradle:".

https://logs.chromium.org/logs/flutter/buildbucket/cr-buildbucket/8727714051273194977/+/u/Run_package_tests/build_all_packages_for_Android_-_legacy_version/stdout

[gmackall]

From triage: Is one of these the legacy file? If so, can we make that file use compileSdk 35 (just copying discussion from internal conversation).

[gmackall]

Also, can we eliminate this conditional logic by just using compileSdk = 35 in both cases? I think that is valid Groovy as well as Kotlin