chore: remove Kotlin version from the default template

template/android/build.gradle

@@ -11,11 +11,8 @@ buildscript {
         google()
         jcenter()
     }
-    ext.kotlinVersion = '1.3.0'
     dependencies {
         classpath("com.android.tools.build:gradle:3.5.3")
-        // for Detox
-        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlinVersion"
         // NOTE: Do not place your application dependencies here; they belong
         // in the individual module build.gradle files
     }