[geolocator_android]: Bump com.android.tools.build:gradle

Bumps com.android.tools.build:gradle from 7.4.2 to 8.6.1.

---
updated-dependencies:
- dependency-name: com.android.tools.build:gradle
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

geolocator_android/android/build.gradle

@@ -8,7 +8,7 @@ buildscript {
     }
 
     dependencies {
-        classpath 'com.android.tools.build:gradle:7.4.2'
+        classpath 'com.android.tools.build:gradle:8.6.1'
     }
 }