Remove source location in server.log

[khoaguin]

Currently we save the log in server.log with redundant source location, e.g. just repeated syftbox.server.middleware:dispatch:14 like in the picture below

This is not useful since we print out logs from middleware.py and this line syftbox.server.middleware:dispatch:14 is almost always repeated, which pollute the log info

This PR removes that information and makes the logs in server.log same with the ones printed out on the console, which is

This is good for our telemetry logs: This

instead of this: