Created by Claude, will be reviewed by @fregante first.

Dims bot PRs in the new React PR lists, which don't have .opened-by, .labels or .Box-row anymore.

Fixes #9797.
Part of #10065.

Checked

• Logged out, repo PR lists with the built extension: all 25 dependabot[bot] rows are dimmed on OctoLinker (0 before), 1 scala-steward row on spotify/scio (0 before), none on a list with only human authors.
• Not checked: global PR search (/pulls/search, needs login) and the issue list. Reviewer: please check those.
• Bot authors in the new list are a[data-testid="author-filter-link"] with aria-label="Filter by author <name>"; the bot label is a button[aria-label="Filter by label bot"].

Test URLs

• Commits: https://github.com/typed-ember/ember-cli-typescript/commits/master?after=5ff0c078a4274aeccaf83382c0d6b46323f57397+174
• Commits by unmarked bot: https://github.com/rust-lang/rust/commits/master?after=c387f012b14a3d64e0d580b7ebe65e5325bcf822+34&branch=master&qualified_name=refs%2Fheads%2Fmaster
• PRs: https://github.com/OctoLinker/OctoLinker/pulls?q=is%3Apr+is%3Aclosed
• PRs by unmarked bot: https://github.com/spotify/scio/pulls?q=is%3Apr+sort%3Aupdated-desc+is%3Aclosed+steward
• PR Commits: https://github.com/pixiebrix/webext-messenger/pull/173/commits
• Global PRs: https://github.com/pulls/search?q=is%3Aopen+is%3Apr+org%3Aapple+archived%3Afalse+draft%3Afalse