Transform Preview for native block Paragraph and Heading can be improved

[andeng1106]

Describe the bug This issue is okay on 5.9.3 but looks off on 6.0. Notes:

• This only apply for the three Stackable blocks: Heading, Text, and Subtitle
• Not sure if this fix will be from Stackable's end or from WordPress

To Reproduce Steps to reproduce the behavior:

1. Add any of the three blocks mentioned in the description above
2. Try to transform it to native block Paragraph or Heading
3. Check preview for native block Paragraph or Heading

Expected behavior WordPress 5.9.3

https://user-images.githubusercontent.com/103395655/168576530-d1c8c04d-24e8-40f3-9f85-0c43445e623f.mp4

Screenshots WordPress 6.0

https://user-images.githubusercontent.com/103395655/168576634-25134686-74d3-468b-ad5f-4e5b4d81ce9c.mp4