report: display plugins in footer

[NickNojiri]

Summary

Adds the plugins used during a run to the report footer's meta block. Plugin categories are detected by their lighthouse-plugin- id prefix (same mechanism as the existing plugin gauge badge) and rendered as a Plugins: <ids> item with the puzzle-piece icon. Reports with no plugins are unchanged.

Includes a new localizable runtimeSettingsPlugins string, regenerated locale/sample fixtures, and unit tests covering both the plugin and no-plugin cases.

Related Issues/PRs

Fixes #9934

[google-cla]

Thanks for your pull request! It looks like this may be your first contribution to a Google open source project. Before we can look at your pull request, you'll need to sign a Contributor License Agreement (CLA).

View this failed invocation of the CLA check for more information.

For the most up to date status, view the checks section at the bottom of the pull request.