space: Cleanup saved objects mappings (#153156)

Co-authored-by: Kibana Machine <42973632+kibanamachine@users.noreply.github.com>
Co-authored-by: Aleh Zasypkin <aleh.zasypkin@gmail.com>

src/core/server/integration_tests/saved_objects/migrations/group2/check_registered_types.test.ts

@@ -135,7 +135,7 @@ describe('checking migration metadata changes on all registered SO types', () =>
         "siem-ui-timeline-note": "13c9d4c142f96624a93a623c6d7cba7e1ae9b5a6",
         "siem-ui-timeline-pinned-event": "96a43d59b9e2fc11f12255a0cb47ef0a3d83af4c",
         "slo": "06733daaa5fbe331fdf3b515171978aff483ccf2",
-        "space": "9542afcd6fd71558623c09151e453c5e84b4e5e1",
+        "space": "7fc578a1f9f7708cb07479f03953d664ad9f1dae",
         "spaces-usage-stats": "084bd0f080f94fb5735d7f3cf12f13ec92f36bad",
         "synthetics-monitor": "96cc312bfa597022f83dfb3b5d1501e27a73e8d5",
         "synthetics-param": "9776c9b571d35f0d0397e8915e035ea1dc026db7",

x-pack/plugins/spaces/server/saved_objects/mappings.ts

@@ -8,6 +8,7 @@
 import { deepFreeze } from '@kbn/std';
 
 export const SpacesSavedObjectMappings = deepFreeze({
+  dynamic: false as false,
   properties: {
     name: {
       type: 'text',
@@ -30,10 +31,9 @@ export const SpacesSavedObjectMappings = deepFreeze({
     disabledFeatures: {
       type: 'keyword',
     },
-    imageUrl: {
-      type: 'text',
-      index: false,
-    },
+    // This field isn't included in the mappings since it doesn't need to be indexed or searched, but it will still
+    // appear in the `_source` field of the `space` document.
+    // imageUrl: { type: 'text' },
     _reserved: {
       type: 'boolean',
     },