Add link for go/rfc-android-k-deprecation (#9905)

Adds a link for a new RFC/design doc.

---------

Co-authored-by: Parker Lougheed <parlough@gmail.com>

Author: dnfield

firebase.json

@@ -500,6 +500,7 @@
       { "source": "/go/rfc-32-bit-ios-support", "destination": "https://docs.google.com/document/d/1Xz8B2w42ZGmrSdvQHo6LVLhiSZBIxnHxZxoZ-8oyRUc/edit", "type": 301 },
       { "source": "/go/rfc-32-bit-ios-unsupported", "destination": "https://docs.google.com/document/d/1cc5EOsuTlbf4dTDTwmkD3aKjS8XEbVCIqi9BFct9XHM/edit?resourcekey=0-Iv0gXDx7nSDCe3YDfxDKqw", "type": 301 },
       { "source": "/go/rfc-android-j-deprecation", "destination": "https://docs.google.com/document/d/1N06Pm1x19AIWorENk6OdmY5T8kMzPJUOZs8aL9VccG4/edit", "type": 301 },
+      { "source": "/go/rfc-android-k-deprecation", "destination": "https://docs.google.com/document/d/1gQGvMk2ydxieivDjO8zqM7DdwOBybKVgoUqZUOCuTo0/edit?usp=sharing&resourcekey=0-ew5kIQr2FPVp7qyydtBQeg", "type": 301 },
       { "source": "/go/rfc-ios8-deprecation", "destination": "https://docs.google.com/document/d/1HtzJLUBnvi-VjcG3XEjwVHQGWeOzlrA77ozp9TvCWVE/edit", "type": 301 },
       { "source": "/go/router-and-widgetsapp-integration", "destination": "https://docs.google.com/document/d/1QodTFmwVr1yk8dyQvoqkeILxvm92oikB1bVhHTtp6R4/edit", "type": 301 },
       { "source": "/go/semantics-roles", "destination": "https://docs.google.com/document/d/1VRagJfHEbehVPa023xGUcFTqe5LgYGU2wYBmnNkwVmA/edit?usp=sharing", "type": 301 },