78915 [flutter_tools] remove suite channel access from web tests (cla: yes, tool, waiting for tree to go green)

78922 Migrate flutter_tool net.dart to null safety (a: null-safety, cla: yes, team, tool)

78923 Migrate android_console to null safety (a: null-safety, cla: yes, team, tool)

78932 Migrate error_handling_io to null safety (a: null-safety, cla: yes, team, tool)

78934 Migrate deferred_components_validator to null safety (a: null-safety, cla: yes, team, tool)

78939 Migrate localizations_utils to null safety (a: null-safety, cla: yes, team, tool)