Shadows stop rendering when their source block moves out of view, even if the shadows themselves are still inside the view

Reproduce:

1. Place some signs.

2. Look at their shadows from an angle where the signs themselves are out of view.

Observed:

When the signs are outside the camera's view, they stop rendering, which is normally fine since they're not visible. However, the shadows they cast—which are still within view—also disappear.

Expected:

Shadows should remain visible even when the signs (their source entityblocks) are outside the player’s view.