Update dependency @testing-library/dom to v8.15.0

Editor assessment

The subject gives the exact package, @testing-library/dom, and the target version v8.15.0, which fully determines the change at a glance. The chore type and deps scope are accurate for a test-library maintenance bump, and no body is needed for a routine version update whose motivation is inherent to dependency upkeep. No footers are present, so there is no noise and nothing malformed. Style is clean: imperative phrasing, no trailing period, no ticket junk, comfortable length, consistent language. The message communicates its full content in one unambiguous line, misleads nowhere, and serves as a clean, publishable example of automated maintenance.