[lib] rename ClientMessageToDevice in tunnelbroker-context.js to TunnelbrokerClientMessageToDevice
Summary:
There are multiple ClientMessageToDevice and other *MessageToDevice types which makes it confusing and not really readable - renaming to make it more specific.
Depends on D12044
Test Plan: Flow
Reviewers: tomek, bartek
Reviewed By: bartek
Subscribers: ashoat
Differential Revision: https://phab.comm.dev/D12045