Remove unnecessary <strong> tags from post title

[pinarol]

This is a quick workaround to remove <strong> tags from post title. We can see those tags on Aztec editor.

Changes reside in WordPress/gutenberg#13763

To Test

Test both on WPAndroid and WPiOS
Main apps PRs: wpandroid, wpios.

1. Test with a new post

• Open a new post
• Type a title
• Switch to Classic editor
• Verify that you don't see <strong> tags

2. Test with an existing post

• Open an existing post with a title
• Switch to Classic editor
• Verify that you don't see <strong> tags

3. Test we don't affect other blocks

• Open a post and add a paragraph/heading block
• Select all and make bold
• Switch to classic editor and see boldness didn't get lost

[daniloercoli]

Tested on wp-android (by using the branch pointed above, and then updating the ref to this branch), and it worked fine!

[etoledom]

I was able to reproduce the original issue and this effectively fixes the problem. 🎉
Tested on WPiOS