Wait for initial element query attributes in tests: fix tests, address PR feedback

Author: lolmaus

addon/-private/modifier.ts

@@ -23,6 +23,7 @@ export type RangeDirection = 'at' | 'from' | 'to';
 interface ResizeObserverService {
   observe(element: HTMLElement, callback?: () => void): void;
   unobserve(element: HTMLElement, callback?: () => void): void;
+  isEnabled: boolean;
 }
 
 /** @internal */
@@ -555,8 +556,8 @@ export default class ElementQueryModifier extends Modifier<ModifierArgs> {
       if (!this.args.named.isDisabled && !this.isDestroying && !this.isDestroyed) {
         this.applyAttributesToElement();
         this.callOnResize();
-        this._maybeRunPromiseResolveHasBeenInstalled();
       }
+      this._maybeRunPromiseResolveHasBeenInstalled?.();
     });
   }
 
@@ -579,16 +580,17 @@ export default class ElementQueryModifier extends Modifier<ModifierArgs> {
 
     this.resizeObserver.observe(this.element, this.didResizeHandler); // eslint-disable-line @typescript-eslint/unbound-method
 
-    if (!this.args.named.isDisabled) {
+    if (!this.args.named.isDisabled && this.resizeObserver.isEnabled) {
       return new Promise((resolve) => {
         this._promiseResolveHasBeenInstalled = resolve;
       });
+    } else {
+      return Promise.resolve();
     }
   }
 
   didUpdateArguments(): void {
-    // @ts-ignore https://github.com/Microsoft/TypeScript/issues/28502#issuecomment-609607344
-    if (!ResizeObserver) return;
+    if (!this.resizeObserver.isEnabled) return;
 
     this.didResizeHandler();
   }