69005 Fix null issue with dynamically updating from zero tabs for TabBar (a: null-safety, cla: yes, f: material design, framework, waiting for tree to go green)

69025 Reland: enable unnecessary_string_escapes and use_raw_strings (#68302) (a: internationalization, a: tests, cla: yes, f: cupertino, f: material design, framework, team, tool, waiting for tree to go green)

69048 Migrate Flutter gallery test to null safety (cla: yes, f: cupertino, f: material design, team)

69050 InheritedTheme updates (cla: yes, f: material design, framework, waiting for tree to go green)

69060 Make Directionality.of non-null (cla: yes, f: cupertino, f: material design, framework, waiting for tree to go green)