[Feature] Add a label/better UI to identify contexts in the trace viewer

Let us know what functionality you'd like to see in Playwright and what your use case is.

Currently working on a dashboard app where tests include running multiple contexts. As an example, one of the feature is chat modal to chat with others. Simple test: User1 sends message to User 2 and verify it is received on User 2 end. While debugging long scenario tests in trace viewer, in the action snapshot section, it is very hard to tell whether the action is from context 1 or context 2. The current way I am using to identifying whether it is user1 or user 2 is go to source and look at the code or really look closely in the action snapshot to differentiate.

Do you think others might benefit from this as well?
Yes, it will help in the following cases:

• For developers who just want to debug the test in trace viewer and unfamiliar with the testing code base
• Long test scenarios which involve similar kind of UI and hard to differentiate

I was thinking of adding a label like C1 or C2 in the actions section.