22541 harden breadcrumb mapped route resolver against invalid entries

tests/phase22/breadcrumb-route-maps-helper.test.cjs

@@ -191,6 +191,34 @@ test("resolveMappedRouteRenderer returns null for unmapped path", () => {
     );
 });
 
+test("resolveMappedRouteRenderer skips invalid map entries and non-function renderer values", () => {
+    const { buildBreadcrumbRendererMaps, resolveMappedRouteRenderer } =
+        loadHelpers();
+
+    const validRenderer = () => "valid";
+
+    const maps = buildBreadcrumbRendererMaps({
+        simpleRouteRenderersByPath: {
+            "/known": "not-a-function"
+        },
+        simpleLinkTextPairRenderersByPath: null,
+        simpleMyPortalRouteRenderersByPath: {
+            "/known": validRenderer
+        },
+        newAppealRouteRenderersByPath: undefined,
+        caseDetailRouteRenderersByPath: {},
+        detailAndAccountRouteRenderersByPath: {}
+    });
+
+    const result = resolveMappedRouteRenderer("/known", maps);
+
+    assert.strictEqual(
+        result,
+        validRenderer,
+        "Expected resolver to skip invalid/non-function entries and return first valid renderer"
+    );
+});
+
 const run = async () => {
     let passed = 0;