Update components entrypoints to use Lit versions for V25

[web-padawan]

Motivation

As part of Lit migration coming in V25 we should update all components to drop Polymer.

Proposed solution

• Replace vaadin-*.js with vaadin-lit-*.js
• Remove Polymer based versions
• Remove any tests that are Polymer specific
  • e.g. missing-import-polymer.test.js in list-box
• Update test snapshots where necessary
  • e.g. vaadin-month-calendar will need updates due to dom-repeat usage.
• Remove @polymer/polymer from dependencies