Remove deleted Firebase ML pods (#7915)

Author: paulb777

SymbolCollisionTest/Podfile

@@ -25,9 +25,6 @@ target 'SymbolCollisionTest' do
     pod 'FirebaseInstanceID', :path => '../'
     pod 'FirebaseInstallations', :path => '../'
     pod 'FirebaseMessaging', :path => '../'
-    pod 'Firebase/MLCommon', :path => '../'
-    pod 'Firebase/MLModelInterpreter', :path => '../'
-    pod 'Firebase/MLVision', :path => '../'
     pod 'FirebasePerformance', :path => '../'
     pod 'FirebaseRemoteConfig', :path => '../'
     pod 'FirebaseStorage', :path => '../'