job-manager: allow guests to access module stats

Problem: flux module stats is generally open to guests,
but the RPC override in the job-manager module is not.

Open job-manager.stats-get to guests.
Add a test to t2202-job-manager.t.

Author: garlick

src/modules/job-manager/job-manager.c

@@ -140,7 +140,7 @@ static const struct flux_msg_handler_spec htab[] = {
         FLUX_MSGTYPE_REQUEST,
         "job-manager.stats-get",
         stats_cb,
-        0
+        FLUX_ROLE_USER,
     },
 
     FLUX_MSGHANDLER_TABLE_END,

t/t2202-job-manager.t

@@ -377,6 +377,11 @@ test_expect_success 'job-manager stats works' '
 	cat stats.out | $jq -e .journal.listeners
 '
 
+test_expect_success 'flux module stats job-manager is open to guests' '
+	FLUX_HANDLE_ROLEMASK=0x2 \
+	    flux module stats job-manager >/dev/null
+'
+
 test_expect_success 'job-manager: remove job-info, job-manager, job-ingest' '
 	flux module remove job-info &&
 	flux module remove job-manager &&