fix(studio): Cmd+; opens Settings (Cmd+, is reserved by macOS) (v0.12.1)

Operator reported Cmd+, doing nothing. macOS reserves Cmd+,
for the native app-Preferences menu item which Flutter Desktop
doesn't wire up — the keystroke is captured by the OS before
the Shortcuts widget sees it.

Adds Cmd+; as the working alternative; keeps Cmd+, registered
too so a future Flutter version (or a native-menu setup) can
light it up. Tooltip on the sidebar gear icon now reads
"Settings (⌘;)" so the discoverable affordance also tells you
the shortcut.

Signed-off-by: flemming-it <stefan.a.flemming@googlemail.com>

pubspec.lock

@@ -79,7 +79,7 @@ packages:
       path: "../fai_dart_sdk"
       relative: true
     source: path
-    version: "0.4.0"
+    version: "0.5.0"
   fake_async:
     dependency: transitive
     description: