[Feature]: Ability to merge Playwright reports from the main run and --last-failed flag

### 🚀 Feature Request

In my CI/CD structure, I first run a certain scope of tests, and then I have the option to rerun failed tests using the `--last-failed` flag.

I would like to have the ability to merge the report from the full scope with the one generated by the `--last-failed` run.

Ideally, the tests from the `--last-failed` report would be treated similarly to retries in the merged report. This would mean having a new tab or section in the summary report, showing the failed tests as if they had been retried in a regular run.

### Example

_No response_

### Motivation

Currently, when using the --last-failed flag, Playwright generates a separate report for the rerun tests, which makes it harder to get a complete picture of the test outcomes. Combining the main report with the --last-failed results would provide a unified view, similar to how retries are displayed, improving test analysis and making it easier to track the progress of failed tests.

This feature would be especially useful in CI/CD pipelines, where developers often rely on reports to quickly assess the overall health of their tests and identify issues. Merging these reports would streamline the process, reduce confusion, and save time.

Start by tracing Playwright's report generation and the --last-failed entry point. Determine how results from the main run and rerun could be combined with reruns represented like retries, then verify that the unified report clearly shows the final outcomes and failed-test history.

Written by the indexing model from the issue text.