Hide Reset on storage filter row when source is externally forced

StoragePageControls.showClearAll fed the actual sourceFilter() into
hasActiveStorageFilters even when the parent forced the scope via
suppressSourceFilter (e.g. Proxmox/Storage mounts StorageSurface
with forcedSourceFilter='proxmox-pve'). Because 'proxmox-pve' is not
the global DEFAULT_STORAGE_SOURCE_FILTER ('all'), the active-filter
check returned true on first paint and the Reset button showed
unconditionally — even though no user-controllable filter had been
changed.

Treat the source filter as DEFAULT_STORAGE_SOURCE_FILTER inside the
active check when suppressSourceFilter is set; the user can't change
that filter on a scoped storage tab, so it must not surface Reset.
suppressNodeFilter was already handled symmetrically; this aligns
sourceFilter with that contract.

frontend-modern/src/components/Storage/StoragePageControls.tsx

@@ -116,7 +116,13 @@ export const StoragePageControls: Component<StoragePageControlsProps> = (props)
         sortDirection: props.sortDirection(),
         groupBy: props.storageFilterGroupBy(),
         statusFilter: props.statusFilter(),
-        sourceFilter: props.sourceFilter(),
+        // When the Source filter is suppressed (a platform page like
+        // Proxmox/Storage forces it to its own scope via
+        // `forcedSourceFilter`), the user cannot change it — so it must not
+        // count as an "active filter" that surfaces the Reset button.
+        sourceFilter: props.suppressSourceFilter
+          ? DEFAULT_STORAGE_SOURCE_FILTER
+          : props.sourceFilter(),
         diskRoleFilter: props.diskRoleFilter?.(),
         diskGroupFilter: props.diskGroupFilter?.(),
       }) ||