Add support for `engagedViews` metric

[altxtech]

Context

This is a new metric added in the latest revision for youtube Analytics and Reporting APIs

https://developers.google.com/youtube/analytics/revision_history

https://developers.google.com/youtube/analytics/metrics

Trying to pull that metrics will not work with Yt::Video#reports. Something like:

# video is Yt::Video
video.reports only: [:views, :engagedViews], by: :day, since: "2025-04-01", until: "2025-05-01"

The engaged views metrics will just get ignored in the resulting report.

[kangkyu]

Thank you for reporting the update!

[kangkyu]

video.reports only: [:views, :engaged_views], by: :day, since: "2025-04-01", until: "2025-05-01"

It will be available like this, if merge #442

[altxtech]

@kangkyu That's perfect. Thank you.

Here's a cool GH trick tough. In GH pull requests, you can use the closes keyword to auto close issues when the PR merges.
https://docs.github.com/en/get-started/writing-on-github/working-with-advanced-formatting/using-keywords-in-issues-and-pull-requests

[kangkyu]

By #444 engagedView is available for video group and playlist as well.