After the AGP upgrade to 8+, I incorrectly deprecated CompileSdkVersion, confused by the deprecation of other {{{}Version{}}} attributes such as {{targetSdkVersion}} and {{{}minSdkVersion{}}}.

Google soft deprecated the argument in AGP 8 and then brought it back in 9, so there's no need to force users to rename it. 

In Unity 6.5 (AGP 9), compileSdk is incorrectly deprecated when it's still working. On Unity 6.0-6.4, it's compileSdkVersion the one incorrectly deprecated. Both should be accepeted as valid in all versions.

Steps to reproduce:*

1. Open an empty project
2. Create a custom Gradle Template

* Publishing Settings > Main Gradle Template

1. Open the generated .gradle file in {{Plugins/Android/}}
2. Replace {{compileSdk}} with {{compileSdkVersion}}
3. {{Build}}

Actual results:* Dialog appears hinting you to rename compileSdkVersion to compileSdk

Expected results: Dialog should not appear, compileSdkVersion is perfectly valid attribute in AGP 8.

Reproducible with versions: 6000.4, 6000.3, 6000.2, 6000.1, 6000.0

Not reproducible with versions: 6000.5 (fixed after AGP upgrade to 9.0)

Tested on (OS): 

Relevant PRs:

• [https://github.cds.internal.unity3d.com/unity/unity/pull/47825]
• [https://github.cds.internal.unity3d.com/unity/unity/pull/91299]