fix: Show a background image in case media doesn't load (#1622)

tests/card-controller/style-manager.test.ts

@@ -1,6 +1,7 @@
 import { beforeEach, describe, expect, it, vi } from 'vitest';
-import { FrigateCardView } from '../../src/config/types';
 import { StyleManager } from '../../src/card-controller/style-manager';
+import { FrigateCardView } from '../../src/config/types';
+import irisLogo from '../../src/images/camera-iris.svg';
 import { createCardAPI, createConfig, createHASS, createView } from '../test-utils';
 
 // @vitest-environment jsdom
@@ -9,6 +10,21 @@ describe('StyleManager', () => {
     vi.resetAllMocks();
   });
 
+  describe('initialize should set common properties', () => {
+    it('should set media background', () => {
+      const api = createCardAPI();
+      const element = document.createElement('div');
+      vi.mocked(api.getCardElementManager().getElement).mockReturnValue(element);
+      const manager = new StyleManager(api);
+
+      manager.initialize();
+
+      expect(
+        element.style.getPropertyValue('--frigate-card-media-background-image'),
+      ).toEqual(`url("${irisLogo}")`);
+    });
+  });
+
   describe('setLightOrDarkMode', () => {
     it('dark mode unspecified', () => {
       const api = createCardAPI();