fix(field): fix form registration in Edge

Author: Mikhail Bashkirov

packages/field/src/FormControlMixin.js

@@ -145,7 +145,7 @@ export const FormControlMixin = dedupeMixin(
        * will requires a `await nextFrame()` in tests
        */
       _registerFormElement() {
-        requestAnimationFrame(() => {
+        this.updateComplete.then(() => {
           this.dispatchEvent(
             new CustomEvent('form-element-register', {
               detail: { element: this },
@@ -164,7 +164,7 @@ export const FormControlMixin = dedupeMixin(
        * @see {@link this._registerFormElement}
        */
       _requestParentFormGroupUpdateOfResetModelValue() {
-        requestAnimationFrame(() => {
+        this.updateComplete.then(() => {
           if (this.__parentFormGroup) {
             this.__parentFormGroup._updateResetModelValue();
           }

packages/fieldset/test/lion-fieldset.test.js

@@ -518,7 +518,8 @@ describe('<lion-fieldset>', () => {
           <lion-input id="firstName" name="firstName" .modelValue="${'Foo'}"></lion-input>
         </lion-fieldset>
       `);
-      await nextFrame();
+      await el.querySelector('lion-input').updateComplete;
+
       const input = el.querySelector('#firstName');
 
       input.modelValue = 'Bar';
@@ -536,7 +537,8 @@ describe('<lion-fieldset>', () => {
           <lion-input id="firstName" name="firstName[]" .modelValue="${'Foo'}"></lion-input>
         </lion-fieldset>
       `);
-      await nextFrame();
+      await el.querySelector('lion-input').updateComplete;
+
       const input = el.querySelector('#firstName');
 
       input.modelValue = 'Bar';
@@ -556,9 +558,11 @@ describe('<lion-fieldset>', () => {
           </lion-fieldset>
         </lion-fieldset>
       `);
-      // 2 times as we are nested here
-      await nextFrame();
-      await nextFrame();
+      await Promise.all([
+        el.querySelector('lion-fieldset').updateComplete,
+        el.querySelector('lion-input').updateComplete,
+      ]);
+
       const input = el.querySelector('#firstName');
       const nestedFieldset = el.querySelector('#name');