Use afterEvaluate to make gradle bundle task work with configureondemand

Summary:
The js bundle task does not run when `org.gradle.configureondemand` is set to true. This uses `afterEvaluate` instead of `gradle.projectsEvaluated` which is executed properly.

Add `org.gradle.configureondemand=true`, run RNTester in release mode and make sure the bundle task is run.

[ANDROID] [BUGFIX] [LOCATION] - Fix release bundle task when org.gradle.configureondemand=true
Closes facebook#18557

Differential Revision: D7396744

Pulled By: mdvacca

fbshipit-source-id: 9ea134cb49e8a087cec16f82b990cd19af76785a

Author: janicduplessis

RNTester/android/app/gradle.properties

@@ -1,4 +1,6 @@
 android.useDeprecatedNdk=true
+org.gradle.parallel=true
+org.gradle.configureondemand=true
 MYAPP_RELEASE_STORE_FILE=my-release-key.keystore
 MYAPP_RELEASE_KEY_ALIAS=my-key-alias
 MYAPP_RELEASE_STORE_PASSWORD=*****

react.gradle

@@ -23,7 +23,7 @@ void runBefore(String dependentTaskName, Task task) {
     }
 }
 
-gradle.projectsEvaluated {
+afterEvaluate {
     // Grab all build types and product flavors
     def buildTypes = android.buildTypes.collect { type -> type.name }
     def productFlavors = android.productFlavors.collect { flavor -> flavor.name }