[keyserver] Reanme getSquadbotMessage to getCommbotMessage and sendSquadbotMessage to sendCommbotMessage

Summary: I'm planning on working in this file and was told do fix this on my way

Test Plan: Crash the app from dev tools on a user and see that the Commbot message gets sent to the keyserver admin.

Reviewers: tomek, atul, jacek

Reviewed By: tomek

Subscribers: ashoat, abosh

Differential Revision: https://phab.comm.dev/D4907