Ignore hold/hangup keyboard shortcuts if no session is selected

blink/sessions.py

@@ -2595,12 +2595,16 @@ class AudioSessionListView(QListView):
                 session.widget.drop_indicator = True
 
     def _SH_HangupShortcutActivated(self):
-        session = self.selectedIndexes()[0].data(Qt.UserRole)
+        selected_indexes = self.selectedIndexes()
+        if selected_indexes:
+            session = selected_indexes[0].data(Qt.UserRole)
             if session.client_conference is None:
                 session.widget.hangup_button.click()
 
     def _SH_HoldShortcutActivated(self):
-        session = self.selectedIndexes()[0].data(Qt.UserRole)
+        selected_indexes = self.selectedIndexes()
+        if selected_indexes:
+            session = selected_indexes[0].data(Qt.UserRole)
             if session.client_conference is None:
                 session.widget.hold_button.click()