Prevented clearAll from removing non-deletable widgets

Signed-off-by: Jasper Boeijenga <jboeijenga@gmail.com>

.changeset/violet-comics-chew.md

@@ -0,0 +1,5 @@
+---
+'@backstage/plugin-home': patch
+---
+
+Fixed bug in CustomHomepageGrid where clearAll did not respect the deletable flag on widgets

plugins/home/src/components/CustomHomepage/CustomHomepageGrid.tsx

@@ -275,7 +275,7 @@ export const CustomHomepageGrid = (props: CustomHomepageGridProps) => {
   };
 
   const clearLayout = () => {
-    setWidgets([]);
+    setWidgets(widgets.filter(w => !w.deletable));
   };
 
   const changeEditMode = (mode: boolean) => {