[Fix] Corrects exploit that allowed to use departamental budget to buy goodie items (#93668)

## About The Pull Request
Adds a check on wherever its self paid or not when buying stuff as self
paid on the budgetering pda program, so it works like a regular cargo
console

## Why It's Good For The Game
Well, behaviors should be consistent, and this looks more like an
oversight. Its also the only way to order goodies with departamental
budgets atm, and the comments on the goodies flag seem to heavily imply
the intent is for this not to happen.

## Proof of work

### Before

<img width="800" height="506" alt="image"
src="https://github.com/user-attachments/assets/6305531c-0b0e-4a25-bff8-7c20c8a72472"
/>


<img width="901" height="551" alt="image"
src="https://github.com/user-attachments/assets/c45e70a1-be6c-4513-b00a-87f2c098c577"
/>

### After

<img width="924" height="734" alt="image"
src="https://github.com/user-attachments/assets/e9862bf9-5ae7-4945-912c-08c509e18058"
/>

<img width="831" height="616" alt="image"
src="https://github.com/user-attachments/assets/4b66aa64-03cd-4724-913f-2fee5489d09f"
/>


## Changelog
🆑
fix: solves an exploit that allowed users to buy goodie packs with the
pda budget program
/🆑

code/modules/modular_computers/file_system/programs/budgetordering.dm

@@ -259,7 +259,7 @@
 				if(isnull(reason) || ..())
 					return
 
-			if(id_card_customer?.registered_account?.account_job) //Find a budget to pull from
+			if(id_card_customer?.registered_account?.account_job && !self_paid) //Find a budget to pull from
 				var/datum/bank_account/personal_department = SSeconomy.get_dep_account(id_card_customer.registered_account.account_job.paycheck_department)
 				if(!(personal_department.account_holder == "Cargo Budget"))
 					var/choice = tgui_alert(usr, "Which department are you requesting this for?", "Choose request department", list("Cargo Budget", "[personal_department.account_holder]"))