Update best_move.py

[SteveConsevage]

Type of pull request:

• Bug fix
• Feature
• Other (performance)

Description:

Moved a small amount of potentially redundant calculation (copying card draw probabilities) into appropriate
else blocks on conditionals

Related Issues:

No related issues

Checklist:

• I have read and followed the contribution guidelines. (full disclosure I forgot to add a comment in the commit but this change is small. Hopefully we'll live on this one)
• I have added necessary documentation (if applicable).
• The changes pass all existing tests.

Screenshots (if applicable):

not applicable

[AttackingOrDefending]

Thanks.