28372 V1.2.1 hotfix.1 — cherry-pick  (cla: yes, team)

28373 Mark non-flaky test as such (a: tests, cla: yes, team)

28376 Revert “Shader warm up (#27660)” (cla: yes, team, team: flakes)

28386 remove personal repo and replace with trivial example for smoke test (cla: yes, tool)

28398 fix red build for analysis (a: typography, cla: yes, framework)

28400 update packages (cla: yes, team)

28431 [Gallery] Fix fortnightly analysis for consts. (cla: yes, team, team: gallery)

28470 Throw assertion error when a Hero has a Hero child. (cla: yes, framework, waiting for tree to go green)