narrow: Return default search title for "group-pm-with" operator.
narrow: Return default search title for "group-pm-with" operator.

Because "group-pm-with" is not a common search operator, instead of
setting a specialized title in the browser and tab, just use the
default title, "Search results".

zulip/zulip,zulip/zulip,zulip/zulip,zulip/zulip,zulip/zulip,zulip/zulip,zulip/zulip