67183 Revert “migrate some material files to nullsafety” (cla: yes, f: material design, framework)

67249 Add detection of drawer open and close in Scaffold widget as a callback method. (cla: yes, f: material design, framework, waiting for tree to go green)

67290 Update documentation for borderWidth/renderBorder on ToggleButtons (cla: yes, f: material design, framework, waiting for tree to go green)

67318 Reland “migrate some material files to nullsafety (#67078)” (cla: yes, f: material design, framework, waiting for tree to go green)

67320 Provide oldLayer where possible (cla: yes, f: cupertino, f: material design, framework, waiting for tree to go green)