Update Gradle wrapper to 8.5 for Java 21 compatibility

Update from Gradle 7.5 to 8.5 to support Java 21, which is required
for the Android Gradle Plugin 8.1.0 and compileSdk 34.

Gradle 8.5+ supports Java 8-21, fixing the "Unsupported class file
major version 65" error on systems with Java 21.

Author: claude

example/android/gradle/wrapper/gradle-wrapper.properties

@@ -2,4 +2,4 @@ distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-7.5-all.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.5-all.zip