Bug 1834602 [wpt PR 40171] - Add WPT for overlay user-agent rules, a=…

…testonly

Automatic update from web-platform-tests
Add WPT for overlay user-agent rules

This was asked for in the HTML PR here:
whatwg/html#9093 (comment)

Change-Id: I94e6960803a3fa9c6e1da4dc4393691b1c969c4b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4555988
Reviewed-by: Rune Lillesveen <futharkchromium.org>
Commit-Queue: Joey Arhar <jarharchromium.org>
Auto-Submit: Joey Arhar <jarharchromium.org>
Cr-Commit-Position: refs/heads/main{#1150875}

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wpt-commits: 363864de8e79f2a88a9ea97841e4c396384b7900
wpt-pr: 40171

UltraBlame original commit: 7cacc3ee42bfcc339942fa4bdf95af8719309de8