[Android] Do not set explicit versions in build.gradle (#4248)

## Description

Gesture Handler loads specific Kotlin version during build. This is
unnecessary and may cause build warnings, such as one described in
#2307.

This PR removes pinning of specific kotlin/gradle versions when Gesture
Handler is not root project, so we fallback to the ones declared by the
root. Unfortunately we can't simply remove those lines, as `spotless`
would fail.

Fixes #2307

## Test plan

Tested that android build correctly in basic-example, expo-example and
standalone app.

---------

Co-authored-by: Copilot Autofix powered by AI <175728472+Copilot@users.noreply.github.com>

Author: m-bert

packages/docs-gesture-handler/docs/fundamentals/installation.mdx

@@ -91,16 +91,6 @@ export function CustomModal({ children, ...rest }) {
 }
 ```
 
-Gesture Handler on Android is implemented in Kotlin. If you need to set a specific Kotlin version to be used by the library, set the `kotlinVersion` ext property in the `android/build.gradle` file and RNGH will use that version:
-
-```groovy
-buildscript {
-    ext {
-        kotlinVersion = "2.1.20"
-    }
-}
-```
-
 #### iOS
 
 While developing for iOS, make sure to install [pods](https://cocoapods.org/) first before running the app:

packages/react-native-gesture-handler/android/build.gradle

@@ -2,17 +2,18 @@ import groovy.json.JsonSlurper
 import com.android.build.gradle.tasks.ExternalNativeBuildJsonTask
 
 buildscript {
-    def kotlin_version = rootProject.ext.has('kotlinVersion') ? rootProject.ext.get('kotlinVersion') : project.properties['RNGH_kotlinVersion']
-
     repositories {
         mavenCentral()
         google()
     }
 
     dependencies {
-        classpath("org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version")
-        classpath("com.android.tools.build:gradle:8.10.1")
-        classpath("com.diffplug.spotless:spotless-plugin-gradle:7.0.4")
+        if (project == rootProject) {
+            def kotlin_version = project.properties['RNGH_kotlinVersion']
+            classpath("org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version")
+            classpath("com.android.tools.build:gradle:8.10.1")
+            classpath("com.diffplug.spotless:spotless-plugin-gradle:7.0.4")
+        }
     }
 }
 

packages/react-native-gesture-handler/android/gradle.properties

@@ -16,4 +16,4 @@ org.gradle.jvmargs=-Xmx2048m -XX:MaxMetaspaceSize=512m -XX:+HeapDumpOnOutOfMemor
 # This option should only be used with decoupled projects. More details, visit
 # http://www.gradle.org/docs/current/userguide/multi_project_builds.html#sec:decoupled_projects
 # org.gradle.parallel=true
-RNGH_kotlinVersion=2.0.21
+RNGH_kotlinVersion=2.2.0