Token metadata api is initialized before gossiper is started.
get_host_id_map REST endpoint cannot function without the fully
initialized gossiper though. The gossiper is started deep in
the join_cluster call chain, but if we move token_metadata api
initialization after the call it means that no api will be available
during bootstrap. This is not what we want.
Make a simple fix by returning an error from the api if the gossiper is
not initialized yet.
Fixes: #24479Closesscylladb/scylladb#24575
(cherry picked from commit e364995e28)
Closesscylladb/scylladb#24587
c644526bf9