Fix cheering issue entering from idle state

Introduced in rP24034.
Units entering cheering from idle state, may not check their surrounding for pottential targets yet, so they will react incorrectly when attacked.
Pointed out by @Freagarach in https://code.wildfiregames.com/D1977?id=10404#inline-52415 and turned out to be issue.

Differential revision: D3455
Fixes: #5966
Reviewed by: @wraitii