Custom text color for advancement title in hover text is overwritten by advancement type default one

The bug

Custom text colors defined for an advancement title are overwritten by the advancement type default one in the hover text.

@dinnerbone: MC-117318: cough cough "and therefore also keep custom formatting"

How to reproduce

1. Download the attached advancement title_test.json and place it in the following directory of your world folder

   data\advancements\custom
   

2. Load the world
3. Grant yourself the advancement

   /advancement grant @s only custom:title_test
   

4. Open the chat and hover over the advancement title