fix(metrics-extraction): Fix n+1 due to filter (#64902)

### Summary
Filter apparently ignores the prefetched `...ondemand_set` so we need to
do this in memory, unfortunately, otherwise have hundreds of short
queries being run.

---------

Co-authored-by: getsantry[bot] <66042841+getsantry[bot]@users.noreply.github.com>

src/sentry/relay/config/metric_extraction.py

@@ -467,9 +467,11 @@ def _can_widget_query_use_stateful_extraction(
     default_version_specs = specs_per_version.get(stateful_extraction_version, [])
     spec_hashes = [hashed_spec[0] for hashed_spec in default_version_specs]
 
-    on_demand_entries = widget_query.dashboardwidgetqueryondemand_set.filter(
-        spec_version=stateful_extraction_version
-    )
+    on_demand_entries = [
+        entry
+        for entry in widget_query.dashboardwidgetqueryondemand_set.all()
+        if entry.spec_version == stateful_extraction_version
+    ]
 
     if len(on_demand_entries) == 0:
         # 0 on-demand entries is expected, and happens when the on-demand task hasn't caught up yet for newly created widgets or widgets recently modified to have on-demand state.