Worldborder behavior is inconsistent

Attached is a link to some GIFs I have recorded: https://imgur.com/gallery/Gbwoaef

Bugs noticed:

• The world border continues to expand or shrink, even when the game is paused in single player

• If the world border is shrinking in single player, and a LAN port is NOT opened, you can continue to survive on the outside of the world border while you are still paused (in my personal world, going outside of the world border will normally instantly kill you.)

• If a LAN port IS opened, or are playing in multiplayer, going outside the world border while it shrinks WILL deal damage (or kill you), even if you are paused

• Two sides of the world border (north and west) seem to have faster and slower animation when growing and shrinking, respectively. The other two sides seem to always animate at the same speed

Suggested fixes:

• In singleplayer, temporarily stop the world border if it is changing size, while paused (similar to how most everything else stops when you pause in singleplayer).

• In multiplayer or when LAN is active, allow the worldborder to continue to change size while paused (similar to how most everything does not stop when you pause while playing multiplayer).

• Adjust the animation speed of the south and east sides of the worldborder, to match the animation speed of the north and west sides, when the worldborder is growing or shrinking

Thanks for reading!