Currently, when I choose "Java" in the sources list and then
click on the page to generate the "click" action, sources reset
to "JavaScript". This is very inconvenient.
This changes the logic to only forcefully change files if either
old or new file is a user file, not a generated one.
Use cases considered:
- run `codegen`, click around, choose different language, click more;
- run script with inspector, pause, click "Record" and record an action;
- same as above, but then continue and see that user source is revealed.
cd53346594