Add "Share course" tooltip to ShareRoomButton (#4375)

* Initial plan

* Add 'Share course' tooltip to ShareRoomButton

Co-authored-by: ggurdin <46800240+ggurdin@users.noreply.github.com>

* Move shareCourse localization to end of intl_en.arb

Co-authored-by: ggurdin <46800240+ggurdin@users.noreply.github.com>

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: ggurdin <46800240+ggurdin@users.noreply.github.com>

lib/l10n/intl_en.arb

@@ -5315,5 +5315,10 @@
   "leaveDesc": "Leave this space and all chats within it",
   "selectAll": "Select all",
   "deselectAll": "Deselect all",
-  "newMessageInPangeaChat": "💬 New message in Pangea Chat"
+  "newMessageInPangeaChat": "💬 New message in Pangea Chat",
+  "shareCourse": "Share course",
+  "@shareCourse": {
+    "type": "String",
+    "placeholders": {}
+  }
 }

lib/pangea/common/widgets/share_room_button.dart

@@ -26,6 +26,7 @@ class ShareRoomButton extends StatelessWidget {
 
     return PopupMenuButton(
       useRootNavigator: true,
+      tooltip: L10n.of(context).shareCourse,
       child: const Icon(Symbols.upload),
       onSelected: (value) async {
         final spaceCode = room.classCode!;