Fix Flutter build issues on x86

Author: pimterry

app/build.gradle

@@ -20,6 +20,13 @@ android {
         versionName "1.6.0"
 
         testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
+
+        // Flutter doesn't support x86 (32-bit), but cronet-embedded includes x86 native
+        // libs. Without this filter, x86 devices pick the incomplete x86 directory and
+        // then crash because libflutter.so is missing.
+        ndk {
+            abiFilters 'armeabi-v7a', 'arm64-v8a', 'x86_64'
+        }
     }
 
     signingConfigs {