[MISSION]Correct pickaxes given in Sandy 2-3

[hooksta4]

I affirm:

• I understand that if I do not agree to the following points by completing the checkboxes my PR will be ignored.
• I understand I should leave resolving conversations to the LandSandBoat team so that reviewers won't miss what was said.
• I have read and understood the Contributing Guide and the Code of Conduct.
• I have tested my code and the things my code has changed since the last commit in the PR and will test after any later commits.

What does this pull request do?

Corrects NPC Grohm to give correct amount of pickaxes during Sandy mission 2-3.

Capture 4:32

Corrects NPC giving more pickaxes than intended.

Steps to test these changes

!addmission 0 6
Talk to Halver in Chateau (or !setmissionstatus [NAME] 1 0
Talk to Grohm
Get 3 pickaxes. (No freebies around here, have you see the price of wood lately)?