77844 Fix some issues flagged by unawaited_futures lint (cla: yes, f: material design, framework, waiting for tree to go green)

77850 [flutter_releases] Flutter 2.0.2 Stable Framework Cherrypicks (a: tests, cla: yes, engine, f: cupertino, f: material design, framework, team, tool)

77859 Do not replace text with semantics labels in selectable text widgets (cla: yes, f: material design, framework, waiting for tree to go green)

77861 Spelling standardization: implementer (cla: yes, d: api docs, waiting for tree to go green)

77863 Autocomplete dartpad examples fix (cla: yes, f: material design, framework)

77864 ShaderMask on web for CupertinoContextMenu (cla: yes, f: cupertino, framework)