83845 [flutter_tools] use ProcessManager.canRun instead of checking for ArgumentErrors (tool, cla: yes, waiting for tree to go green)

83847 [flutter_tools] check for empty host in protocol_discovery (tool, cla: yes, waiting for tree to go green)

83852 Remove globals from android application_package (team, tool, cla: yes, waiting for tree to go green, tech-debt)

83854 Migrate deferred_components_prebuild_validator to null safety (tool, cla: yes, waiting for tree to go green, a: null-safety)

83855 Migrate iOS project migrations to null safety (team, tool, cla: yes, waiting for tree to go green, a: null-safety)