62951 migrate part of painting to nullsafety (a: null-safety, framework, waiting for tree to go green)

62954 fix some comment errors for clipBehavior’s default value (framework, waiting for tree to go green)

62972 non-nullable LicenseEntry.packages (framework)

62990 [hotfix] flutter create -t plugin remove no-op iOS folder and set sdk min to 1.20.0 (engine, framework, team, tool)

63005 Incomplete app widget error (framework, waiting for tree to go green)

63007 Ignore dead_code hints for weak-only null checks. (framework)

63012 Remove old button references from the Stepper widget (f: material design, framework)

63013 Remove old button references from routes_test (framework, waiting for tree to go green)