Change labels for default insights charts

ee/fixtures/insights/default.yml

@@ -20,10 +20,10 @@ issues:
         filter_labels:
           - bug
         collection_labels:
-          - priority::1
-          - priority::2
-          - priority::3
-          - priority::4
+          - P::1
+          - P::2
+          - P::3
+          - P::4
         group_by: month
     - title: Bugs created per month by Severity
       type: stacked-bar
@@ -32,10 +32,10 @@ issues:
         filter_labels:
           - bug
         collection_labels:
-          - severity::1
-          - severity::2
-          - severity::3
-          - severity::4
+          - S::1
+          - S::2
+          - S::3
+          - S::4
         group_by: month
 mergeRequests:
   title: Merge Requests Dashboard