gear_menu: Open group settings overlay with "#groups/your" hash.

This commit fixes the bug in browser back button behavior when
opening the groups overlay from gear menu. The bug was caused
due to browser history containing both "#groups" and "#groups/your"
entries, which essentially resulted in a "#groups/your" -> "#groups"
-> "#groups/your" cycle and thus nothing happend on clicking
browser back button.

The case for a user manually typing "#groups" url would be handled
in next commit.

(cherry picked from commit eced3d9d6a)

web/templates/gear_menu_popover.hbs

@@ -67,7 +67,7 @@
                 </li>
                 {{#unless is_guest}}
                 <li class="link-item navbar-dropdown-menu-inner-list-item hidden-for-spectators">
-                    <a href="#groups" class="navigate-link-on-enter navbar-dropdown-menu-link">
+                    <a href="#groups/your" class="navigate-link-on-enter navbar-dropdown-menu-link">
                         <i class="navbar-dropdown-icon zulip-icon zulip-icon-user-cog" aria-hidden="true"></i> {{t 'Group settings' }}
                     </a>
                 </li>