vaadin-form-layout snippet should use Vaadin components

[anssit]

Steps to reproduce

Drag and drop a vaadin-form-layout into the design.

Actual behavior

A vaadin-form-layout appears with a single vaadin-form-item child that's made of a <label> and an <input>.

Expected behavior

Instead of <input>, have a <vaadin-text-field> inside the form item.

When adding new form items, make sure they follow the same pattern.

Other similar snippets should be updated respectively to make use of the Lumo themed Vaadin components so that the design looks beautiful and consistent all the time.

IDE, Designer and OS version

Designer 3.0.0.beta3, any OS, any IDE.

[ripla]

Will be fixed with new snippets: #1650 and #1651