dateMenu: Fix missing text style for no locations state

- add class to the header when there are no locations so the text appears clickable

Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/3169>

data/theme/gnome-shell-sass/widgets/_calendar.scss

@@ -251,6 +251,11 @@
         @extend %heading;
         color: $insensitive_fg_color;
 
+         // change style when no location is configured
+        &.no-location {
+          color: $fg_color;
+        }
+
         &.location {
           font-weight: normal;
         }

js/ui/dateMenu.js

@@ -727,6 +727,11 @@ class WeatherSection extends St.Button {
         else
             this._titleLabel.text = _('Select weather location…');
 
+        if (this._weatherClient.hasLocation)
+            this._titleLabel.remove_style_class_name('no-location');
+        else
+            this._titleLabel.add_style_class_name('no-location');
+
         this._forecastGrid.visible = this._weatherClient.hasLocation;
         this._titleLocation.visible = this._weatherClient.hasLocation;