Move monitoring dashboard_spec to Jest

spec/frontend/environment.js

@@ -40,6 +40,7 @@ class CustomEnvironment extends JSDOMEnvironment {
 
     this.global.fixturesBasePath = `${ROOT_PATH}/tmp/tests/frontend/fixtures${IS_EE ? '-ee' : ''}`;
     this.global.staticFixturesBasePath = `${ROOT_PATH}/spec/frontend/fixtures`;
+    this.global.IS_EE = IS_EE;
 
     // Not yet supported by JSDOM: https://github.com/jsdom/jsdom/issues/317
     this.global.document.createRange = () => ({

spec/frontend/test_setup.js

@@ -73,6 +73,9 @@ expect.extend(customMatchers);
 // Tech debt issue TBD
 testUtilsConfig.logModifiedComponents = false;
 
+// Stub for URL.createObjectURL
+window.URL.createObjectURL = function createObjectURL() {};
+
 // Basic stub for MutationObserver
 global.MutationObserver = () => ({
   disconnect: () => {},