Upgrade gradle plugin (#4751)

Summary:
[android] Upgrade gradle project
Makes us compatible with Android Studio Flamingo and unlocks upgrades to Kotlin
(which we need to be in sync with fbsource).

Pull Request resolved: https://github.com/facebook/flipper/pull/4751

Test Plan:
- ./gradlew :android:assembleDebug
- Android Studio Sync
- CI

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Stack created with [Sapling](https://sapling-scm.com). Best reviewed with [ReviewStack](https://reviewstack.dev/facebook/flipper/pull/4751).
* https://github.com/facebook/flipper/issues/4759
* https://github.com/facebook/flipper/issues/4758
* https://github.com/facebook/flipper/issues/4757
* https://github.com/facebook/flipper/issues/4756
* https://github.com/facebook/flipper/issues/4755
* https://github.com/facebook/flipper/issues/4754
* https://github.com/facebook/flipper/issues/4753
* https://github.com/facebook/flipper/issues/4752
* __->__ https://github.com/facebook/flipper/issues/4751

Reviewed By: aigoncharov

Differential Revision: D46068236

Pulled By: passy

fbshipit-source-id: 707422134b49c0d940b663f6f40937fe6561a038

android/plugins/leakcanary/build.gradle

@@ -8,6 +8,7 @@
 apply plugin: 'com.android.library'
 
 android {
+    namespace 'com.facebook.flipper.plugins.leakcanary'
     compileSdkVersion rootProject.compileSdkVersion
     buildToolsVersion rootProject.buildToolsVersion