hotspots: Use ugettext_lazy for i18n.
hotspots: Use ugettext_lazy for i18n.

Since ALL_HOTSPOTS is a global object, it is initialized
at the time the backend server is started. Hence, the
title and description is translated only once. Using
ugettext_lazy makes sure that the strings are translated
in each and every request according to the language
of the user.

Fixes #16224

zulip/zulip,showell/zulip,zulip/zulip,rht/zulip,showell/zulip,andersk/zulip,rht/zulip,hackerkid/zulip,hackerkid/zulip,punchagan/zulip,punchagan/zulip,eeshangarg/zulip,showell/zulip,andersk/zulip,punchagan/zulip,andersk/zulip,eeshangarg/zulip,eeshangarg/zulip,rht/zulip,hackerkid/zulip,zulip/zulip,zulip/zulip,punchagan/zulip,eeshangarg/zulip,eeshangarg/zulip,andersk/zulip,andersk/zulip,kou/zulip,andersk/zulip,kou/zulip,kou/zulip,kou/zulip,zulip/zulip,hackerkid/zulip,hackerkid/zulip,zulip/zulip,andersk/zulip,hackerkid/zulip,showell/zulip,showell/zulip,showell/zulip,eeshangarg/zulip,punchagan/zulip,hackerkid/zulip,rht/zulip,showell/zulip,kou/zulip,punchagan/zulip,kou/zulip,kou/zulip,punchagan/zulip,eeshangarg/zulip,rht/zulip,zulip/zulip,rht/zulip,rht/zulip