Add the font size and font family dropdowns to the TinyMCE editor

[marklchaves]

Describe the feature request

See this video excerpt.

https://www.youtube.com/watch?v=HJIg-wXXuzI&t=966s

Use case

Because there's no content font-size option in the Popup Maker theme editor, it will give classic editor customers more font control for the text inside popups.

Also, switching to the block editor allows you to control text font in paragraph blocks for example. But you lose things like preview, enable/disable, and categories and tags when switching block editor support in Popup Maker

Example screenshots (if any)

Video: https://www.youtube.com/watch?v=HJIg-wXXuzI&t=966s

Gist: https://gist.github.com/marklchaves/9f0aa613662e6c6a69a1fd43cd81055c