[Regression] JENKINS-70128 Dismiss button unreadable in old data monitor with dark theme

[Basil Crow]

jenkinsci/jenkins#7364 has introduced a regression on the weekly line. JENKINS-70128 contains the steps to reproduce, expected result, and actual result. At the time of this writing, jenkinsci/jenkins#7364 (comment) remains unacknowledged.

This regression has not yet reached the stable (LTS) line, currently scheduled to ship in about a month. To ensure that the next LTS release ships without the issue, options include opening a pull request to resolve the issue or reverting the original change.