fix: add safe-area-inset-bottom padding to gf-page-tabs component

The tab navigation component was missing padding-bottom: env(safe-area-inset-bottom)
after the refactoring in #6797 extracted the tabs into a standalone <gf-page-tabs>
component. The safe-area padding was left behind on the global .page class, but
because the component enforces height: 100%, it overrides the parent's padding.

This causes the bottom navigation bar to overlap the iOS home indicator on
mobile devices.

Fix: add padding-bottom: env(safe-area-inset-bottom) (with constant() fallback
for older iOS versions) directly to the :host of the page-tabs component.

Closes #6878

libs/ui/src/lib/page-tabs/page-tabs.component.scss

@@ -4,6 +4,8 @@
   display: flex;
   flex-direction: column;
   height: 100%;
+  padding-bottom: env(safe-area-inset-bottom);
+  padding-bottom: constant(safe-area-inset-bottom);
   width: 100%;
 
   .external-link-icon {