bug: example error with empty config key

[bazuka5801]

Expected Behavior

Actual Behavior and Steps to Reproduce the Problem

P.s. with adding config key

Error from browser console (android device)

Uncaught (in promise) Attempt to invoke virtual method 'com.google.firebase.firestore.CollectionReference com.google.firebase.firestore.FirebaseFirestore.collection(java.lang.String)' on a null object reference

Error from android studio

E/FirestorePlugin: Error processing collection get in thread
    java.lang.NullPointerException: Attempt to invoke virtual method 'com.google.firebase.firestore.CollectionReference com.google.firebase.firestore.FirebaseFirestore.collection(java.lang.String)' on a null object reference
        at uk.co.reallysmall.cordova.plugin.firestore.CollectionGetHandler.handle(CollectionGetHandler.java:38)
        at uk.co.reallysmall.cordova.plugin.firestore.FirestorePlugin.execute(FirestorePlugin.java:73)
        at org.apache.cordova.CordovaPlugin.execute(CordovaPlugin.java:98)
        at org.apache.cordova.PluginManager.exec(PluginManager.java:132)
        at com.getcapacitor.MessageHandler.callCordovaPluginMethod(MessageHandler.java:107)
        at com.getcapacitor.MessageHandler.postMessage(MessageHandler.java:51)
        at android.os.MessageQueue.nativePollOnce(Native Method)
        at android.os.MessageQueue.next(MessageQueue.java:363)
        at android.os.Looper.loop(Looper.java:173)
        at android.os.HandlerThread.run(HandlerThread.java:67)

Specifications

• Plugin version: 4.1.1
• Framework: --
• Framework version: --
• Operating system: maxOs Big Sure beta 11.0