Pasting text on a blank line inserts a new line before and after

### Expected
Pasting text should not add additional newlines.

### Observed
When I copy and paste a single word or sentence onto a newline in the middle of existing content, it inserts a blank line both before and after.

### Reproduced
> 1. Copy some text (from Simplenote or elsewhere) without any newlines.
> 2. Go to a note in Simplenote that has some content already.
> 3. Long press on a new line and paste. It's easiest to see if you do this right before or after existing content.
> 4. Observe that a new line gets added before and after pasted content.

Reproduced on latest beta (4.14.0.2) / iOS 13.2.3

Screenshots:


Start by reproducing the paste behavior in the iOS app using the four steps in the issue, ideally with content before and after the blank line. Verify that pasting a single word or sentence does not add a newline before or after it, including near existing content.

Written by the indexing model from the issue text.