Style extended when adding a space on API 26+

[0nko]

Reproduced

In the demo text after "Italic":

1. Add a new line and type "a"
2. Toggle bold style
3. Type "b"
4. Place cursor between "a" and "b"
5. Add a space
6. Note that the bold formatting is extended to "a"

Tested

Emulator on API 26

[daniloercoli]

Also reported in gb-mobile here: https://github.com/wordpress-mobile/gutenberg-mobile/issues/824

(Make sure to have the Gboard keyboard in use)

• Start with two words text like "two words".
• Place the caret between the space and the "w".
• Tap on "B" to turn on bold.
• Type a few chars and press "space".