Add integration tests for trace limit handling

What does this MR do?

1. Changes the visualization of job output limit exceeded from being error-like (red color) to being warning-like (yellow color). moved to !2765 (merged)
2. Adds a clear information that the limit exceeding doesn't stop job execution but just collection of output. moved to !2765 (merged)
3. Adds integration tests to guard the behavior of job output limiting.

Why was this MR needed?

Current visualization of the job output limiting is confusing to the users. It looks like an error, while the job is still executed and may even properly succeed. For new GitLab CI/CD users it may be also unknown that when such warning is printed, the job is still being executed (they may not notice the running status icon). Therefore the visualization and wording of the limiting warning was changed to make it more clear to the user.

And as recent change have introduced a regression in job output limiting behavior integration tests to cover that were added.

What's the best way to test this MR?

What are the relevant issue numbers?

Closes #27561 (closed)