76820 Update dartdoc to 0.40.0. (cla: yes, team, waiting for tree to go green)

76829 Remove dead ensureDirectoryExists (cla: yes, team, tool, waiting for tree to go green)

76831 [customer_testing] Refactor runner to be testable (cla: yes, team, waiting for tree to go green)

76838 Remove dart_plugin_registry_test timeouts (cla: yes, team, team: flakes, waiting for tree to go green)

76898 Fix prepare package (cla: yes, team)

76960 Move flaky flag  from the remainin mac/ios tests. (cla: yes, team)

77004 Removed ListTile accentColor dependency (cla: yes, f: material design, framework, team, waiting for tree to go green)