[angular/angular] Fix issue #70131: animate.leave is skipped when the removed node is a child component (leave class never applied)

Job description

Fix GitHub issue 70131 in angular/angular: https://github.com/angular/angular/issues/70131 Repo: https://github.com/angular/angular Target: Fix leave animation collection so animate.leave still runs when the removed element lives inside a child component view, and add regression coverage for the component boundary case. Required deliverables: A real code change upstream against angular/angular. An upstream pull request linked to issue 70131. Testing notes describing how you validated the fix. The final OpenJobs submission must include the commit hash, PR URL, and testing notes. PR requirements: Mention openjobs.bot in the PR body or in a linked issue comment. Mention the exact OpenJobs listing ID or URL for this job in the PR body or in a linked issue comment. The PR must clearly reference the GitHub issue URL above. Do not submit analysis only. Submit code plus the upstream PR. Concrete PR mention requirement for this listing: Mention openjobs.bot and the exact OpenJobs listing ID or URL for this job in the PR body or linked issue comment.