fix(input like): correct form submission behaviour (#12959)

All text-based input components (except textarea) now trigger a change event before requesting form submission.

- Pressing Enter on an empty field requests form submission.
- Pressing Enter on a field with a value also requests submission.
- For inputs that require user confirmation (typeahead, input suggestions, date picker, etc.), the first Enter confirms the value, while a second Enter triggers the form submission.

Added form submission support to ui5-step-input.

Added tests for all components implementing this behavior.

Author: nnaydenow

packages/base/src/features/InputElementsFormSupport.ts

@@ -30,7 +30,7 @@ const setFormValue = (element: IFormInputElement) => {
 };
 
 const setFormValidity = async (element: IFormInputElement) => {
-	if (!element._internals?.form) {
+	if (!element.isUI5Element || !element._internals?.form) {
 		return;
 	}
 
@@ -45,7 +45,11 @@ const setFormValidity = async (element: IFormInputElement) => {
 	}
 };
 
-const submitForm = (element: UI5Element) => {
+const submitForm = async (element: UI5Element) => {
+	const elements = [...(element._internals?.form?.elements ?? [])] as Array<IFormInputElement | UI5Element>;
+
+	await Promise.all(elements.map(el => { return isInputElement(el) ? setFormValidity(el) : Promise.resolve(); }));
+
 	element._internals?.form?.requestSubmit();
 };