Revert "chore: bump flutter version"

This reverts commit 47fd90e4a5.

android/build.gradle

@@ -16,14 +16,6 @@ allprojects {
 rootProject.buildDir = '../build'
 subprojects {
     afterEvaluate { project ->
-    if (project.hasProperty('android')) {
-        project.android {
-            if (namespace == null) {
-                namespace project.group
-            }
-        }
-    }
-
         if (project.extensions.findByName("android") != null) {
             Integer pluginCompileSdk = project.android.compileSdk
             if (pluginCompileSdk != null && pluginCompileSdk < 31) {