68227 Selecting spaces (cla: yes, f: cupertino, f: material design, framework)

68241 Migrate missed tests (cla: yes, f: cupertino, f: material design, framework, waiting for tree to go green)

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

68508 Remove references to CupertinoDialog (cla: yes, f: cupertino, framework, waiting for tree to go green)

68642 Sound null safety for framework and flutter_test (a: tests, cla: yes, d: examples, f: cupertino, f: material design, framework, team)