91453 Remove extensions (framework, f: material design, cla: yes, waiting for tree to go green)

91454 Roll Engine from 76c8115c6d61 to 8d64613c9b4b (1 revision) (cla: yes, waiting for tree to go green)

91455 Migrate android build target to null safety (tool, cla: yes, waiting for tree to go green, a: null-safety, tech-debt)

91457 Move DeviceManager into null migrated globals library (tool, cla: yes, a: null-safety, tech-debt)

91459 Revert gradle roll (team, tool, a: accessibility, cla: yes, d: examples, integration_test)