Remove the unnecessary google-services plugin (#1397)

Author: Kevin Li

MapboxAndroidDemo/build.gradle

@@ -3,7 +3,6 @@ apply plugin: 'kotlin-android'
 apply plugin: 'kotlin-android-extensions'
 apply plugin: 'com.github.triplet.play'
 apply plugin: 'com.google.firebase.crashlytics'
-apply plugin: 'com.google.gms.google-services'
 apply plugin: 'org.jmailen.kotlinter'
 apply from: "$project.rootDir/gradle/script-git-version.gradle"
 apply from: "$project.rootDir/gradle/gradle-dependencies-graph.gradle"
@@ -186,4 +185,4 @@ apply from: "${rootDir}/gradle/checkstyle.gradle"
 apply plugin: 'kotlin-android-extensions'
 if (getGradle().getStartParameter().getTaskRequests().toString().contains("Release")) {
     apply plugin: 'com.google.gms.google-services'
-}
+}