78375 Removed accentColor refs from API docs (cla: yes, f: material design, framework)

78378 Removed accentColor and accentTextTheme dependencies from flutter_gallery (cla: yes, f: material design, team, waiting for tree to go green)

78395 fix the position of popup menu when have unsafe area (cla: yes, f: material design, framework, waiting for tree to go green)

78428 Include validation for DatePicker and DateRangePicker inputOnly mode (cla: yes, f: date/time picker, f: material design, framework)

78449 Remove accentColor et al.  from tests (cla: yes, f: material design, framework, team)

78450 Add restorationId to Material/CupertinoPage (cla: yes, f: cupertino, f: material design, framework, waiting for tree to go green)