World border "warning" effect shows when the border grows

World borders still warn players when expanding in size.

Steps to reproduce:

1. Set the world border distance to a small value (e.g. /worldborder set 100)
2. Make the world border distance grow over some time (e.g. /worldborder set 1000 5)

Observed result:
World border "warning" effect shows when it is growing.

Expected behavior:
World border "warning" effect doesn't show.