Coloured text on signs not save the colour on the new lines (but shows on UI)

Verification builds:
1.2.8

Summary:
When using coloured text on signs, the formatting carries over to new lines in the sign editing UI, but doesn't show on the placed sign. This is confusing to the user as to what they can expect to see written on the completed sign.

Steps to Reproduce:

1. Load a creative world
2. Obtain and place a sign
3. Type §a (alt + 0167) and any text
4. Press enter
5. In the new line type more text
6. Exit sign UI

Observed Results:
Notice that text is formatted in the new lines in the sign UI, but is not formatted on the sign placed within the world.

Expected Results:
The text on the UI should be consistent with what appears on the actual placed sign. Whether the formatting should continue to the next line or not is a design decision, but either way the text in the UI and on the placed sign should match.

Screenshots/Videos attached: Yes

Notes:
Keyword for search: color