Use this code:
if (!getGradle().getStartParameter().getTaskRequests()
.toString().contains("Develop")){
apply plugin: 'com.google.gms.google-services'
}
getGradle().getStartParameter().getTaskRequests().toString()
returns something like [DefaultTaskExecutionRequest{args=[:app:generateDevelopDebugSources],projectPath="null"}]
so as stated in the comments Develop
must start with an uppercase.