Text within boss bars is unaffected by the "Text Background" accessibility option

The Bug:

Text within boss bars is unaffected by the "Text Background" accessibility option.

Steps to Reproduce:

1. Navigate to the accessibility settings menu.
2. Set the "Text Background Opacity" slider to "0%" and the "Text Background" button to "Everywhere".
3. Set up a boss bar by using the commands provided below.

   /bossbar add test "MC-158317"

   /bossbar set minecraft:test players @s

4. Observe if the text within the boss bar is affected by the "Text Background" accessibility option.

Observed Behavior:

Text within boss bars is unaffected by the "Text Background" accessibility option.

Expected Behavior:

Text within boss bars would be affected by the "Text Background" accessibility option.