fix(file-format): hide rarely-used 'Use Currency From File' toggle

Multi-currency Bank Accounts (one account holding several currencies in
parallel) exist with some western banks like Revolut/Wise, but in AZ the
convention is one Bank Account per currency. The toggle was extra noise
on the File Format tab for every user.

Kept the field and the underlying parse/import logic intact (hidden=1
only). Removing the hidden flag re-exposes it if a real multi-currency
case ever shows up.

.gitignore

@@ -5,3 +5,4 @@
 tags
 node_modules
 __pycache__
+Screenshot*.png

jey_erp/jey_erp/doctype/bank_statement_importer/bank_statement_importer.json

@@ -207,6 +207,7 @@
    "description": "Off: every imported Bank Transaction gets its Bank Account's currency.\nOn: the parsed Currency column on each row is used, falling back to the Bank Account's currency when empty. Enable only for multi-currency Bank Accounts where the statement actually carries per-row currency.",
    "fieldname": "use_currency_from_file",
    "fieldtype": "Check",
+   "hidden": 1,
    "label": "Use Currency From File"
   },
   {