Text fields render translucent pixels as opaque

Discovered while testing MC-269437

The bug

If text_field or text_field_highlighted are given textures containing translucent pixels, they will render these pixels as entirely opaque in-game, which is inconsistent with other widgets such as buttons and sliders, which support translucent pixels just fine.

How to reproduce

1. Download and apply the attached resource pack

2. Look at any menu containing a text field

Expected results

The text field would have an opaque border and translucent center, just like the buttons.

Actual results

The text field is completely solid.

How to fix

Allow text fields to use translucent pixels.

Further notes

The attached screenshots were taken before I retextured buttons in this specific resource pack.