40174 Keep Flutter.framework binaries writable so they can be code signed (cla: yes, tool)

40175 Ensure we send hot restart events for flutter web (cla: yes, tool)

40179 Update PopupMenu layout (cla: yes, f: material design, framework, severe: API break)

40181 Update Kotlin and Gradle version (a: accessibility, cla: yes, d: examples, team, team: gallery, tool)

40186 Add shortcuts and actions for default focus traversal (a: desktop, cla: yes, framework, team)

40189 Dark mode CupertinoNavigationBar (cla: yes, f: cupertino, framework, will affect goldens)

40190 disable bitcode for hello_world (cla: yes, d: examples, team)