How to stop Android Studio suggesting "Insert App Indexing" quick fix?

Brilliant indeed, took me an hour to undo the changes it caused and to turn it off for good.

File -> Settings -> Plugins -> Firebase App Indexing -> uncheck.

Restart Android Studio and it will be gone.

Note that this will remove the plugin, don't know if there is a way to just disable the quickfix suggestion.

If you need Firebase plugin enabled. Uncheck this function: File->Settings->Editor->Intentions->"Android"\"Insert App Indexing API Code". This disables only annoing quickfix suggestion.