[RNMobile] Cursor's position is sometimes off while dictating on iOS

[SiobhyB]

Description

While dictating text in the editor on iOS, there are some occasions where the cursor's position is either off by one, or when it briefly appears out of place on a new line.

Reported at #49452 (comment) and #49452 (comment)

Step-by-step reproduction instructions

Incorrect placement

• Begin dictating text into a paragraph block.
• Without ending dictation, move the cursor into the middle of the text and begin dictating.
• Notice that the cursor can appear out of place when the text moves onto a new line.
• The cursor will correct itself as you continue dictating, and the text will remain in the correct position.

Note, this doesn't happen if you end dictation and then re-start it to add text into the middle of the text.

Off by one placement

• Navigate to My Site → Posts and create a new post.
• Tap on "Start writing..." to focus the default paragraph block.
• Activate the iOS dictation feature and dictate "Mary had a little lamb its fleece was white as snow"
• Place the cursor after "little" then deactivate iOS dictation
• Activate the iOS dictation feature and dictate "Old MacDonald had a Farm"
• Confirm that the cursor is off by one.

Expected behaviour

I'd expect the cursor to always remain in the position at which the text is being dictated.

Actual behaviour

There are some cases where the cursor's placement is off.

Device information

• Device: iPhone XR
• Operating system: iOS 16.5
• WordPress app version: 22.6