gradle repo priority (#22041)

Summary:
Changed gradle repo list to have consistent priority. mavenLocal is top priority because it requires manual setup, also won't conflict with other repos.
Pull Request resolved: https://github.com/facebook/react-native/pull/22041

Differential Revision: D12871549

Pulled By: hramos

fbshipit-source-id: c86730fde956dca77174c6454fdcb005a5eec8a9

local-cli/templates/HelloWorld/android/build.gradle

@@ -9,8 +9,8 @@ buildscript {
         supportLibVersion = "27.1.1"
     }
     repositories {
-        jcenter()
         google()
+        jcenter()
     }
     dependencies {
         classpath 'com.android.tools.build:gradle:3.1.4'
@@ -22,8 +22,8 @@ buildscript {
 
 allprojects {
     repositories {
-        google()
         mavenLocal()
+        google()
         jcenter()
         maven {
             // All of React Native (JS, Obj-C sources, Android binaries) is installed from npm