Add internet permissions to the AdMob resources in the open source build.

When building the AdMob resources, the linter can complain about not having the INTERNET permission enabled.

PiperOrigin-RevId: 273846570

Author: a-maurice

admob/admob_resources/build.gradle

@@ -36,7 +36,9 @@ android {
 
   sourceSets {
     main {
-      manifest.srcFile '../../android_build_files/AndroidManifest.xml'
+      // Use the manifest that gives access to the internet, as some of the
+      // AdMob classes have linter problems without it.
+      manifest.srcFile '../../android_build_files/AndroidManifest-internet.xml'
       java {
         srcDirs = ['../src_java/com/google/firebase/admob/internal/cpp']
       }

android_build_files/AndroidManifest-internet.xml

@@ -0,0 +1,5 @@
+<?xml version="1.0" encoding="utf-8"?>
+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+          package="com.google.FirebaseCppSdkBuild">
+  <uses-permission android:name="android.permission.INTERNET"/>
+</manifest>