test(mobile): anchor dashboard nav scope checks to the sidebar container (#4712)

tests/test_dashboard_link_ui.py

@@ -88,5 +88,10 @@ def test_mobile_dashboard_link_is_scoped_hidden_in_narrow_viewport_css():
 def test_desktop_dashboard_link_button_stays_in_desktop_nav():
     rail_nav = re.search(r'<nav class="rail".*?</nav>', INDEX_HTML, re.DOTALL).group(0)
     assert 'id="dashboardRailBtn"' in rail_nav
-    mobile_nav = re.search(r'<div class="sidebar-nav">.*?</div>', INDEX_HTML, re.DOTALL).group(0)
+    mobile_nav_match = re.search(
+        r'<div class="sidebar-nav">([\s\S]*?)</div>\s*(?=<!--)',
+        INDEX_HTML,
+    )
+    assert mobile_nav_match is not None
+    mobile_nav = mobile_nav_match.group(0)
     assert 'id="dashboardMobileBtn"' in mobile_nav