67542 Revert “Remove examples/catalog” (a: accessibility, cla: yes, d: examples, team)

67545 Reland removal of examples/catalog (a: accessibility, cla: yes, d: examples, f: material design, framework, team, waiting for tree to go green)

67940 Fix NestedScrollView sample code (a: quality, cla: yes, d: api docs, d: examples, documentation, framework, waiting for tree to go green)

67946 Migrate Scaffold SnackBars in the framework to ScaffoldMessenger (a: tests, cla: yes, d: api docs, d: examples, documentation, f: material design, framework, team, waiting for tree to go green)

68361 Build iOS apps using Swift Packages (cla: yes, d: examples, team, tool, waiting for tree to go green)