Lead stops rendering when the entity it's attached to is off-screen

Partner Rank: 3

Verification builds: 1.16.61
Regression builds: 1.14.6005

Summary: When a lead is attached to two entities, it stops rendering if one of those two entities (the destination one, I think) stops rendering.

Impact: This breaks a visual effect in one of our upcoming maps. However, I have a simple workaround (increase visual bounds) and will submit a patched version. Therefore, this bug is not currently an issue for our team.

Repro Steps:

1. Fly up high and place a fence
2. Spawn a mob
3. Use a lead on the mob and tie it to the fence, so it's hanging down
4. Move until the mob is off-screen

Expected Results: Lead remains visible at all times.

Observed Results: Lead disappears visually.

Screenshots/Videos attached: Yes