74280 Check VM service URI is valid before attempting to start DDS (Re-upload #73998) (cla: yes, tool, waiting for tree to go green)

74285 Pass only Uri to package:http APIs (cla: yes, team, tool, waiting for tree to go green)

74293 [flutter_tools] Fix ignoring of Flutter tester exitCode (cla: yes, tool)

74306 Rephrase null safety mode (cla: yes, tool)

74348 Adjust desktop feature flag (cla: yes, tool)

74355 [flutter_releases] Flutter Stable 1.22.6 Framework Cherrypicks (cla: yes, engine, tool)

74359 Skip flutter_immediately_exit_test (cla: yes, team, tool)