feat: remove german sales invoice validation (#24441)

This can be better achieved via Customize Form
(mandatory and mandatory_depends_on)
diff --git a/erpnext/hooks.py b/erpnext/hooks.py
index 14377e1..1c20555 100644
--- a/erpnext/hooks.py
+++ b/erpnext/hooks.py
@@ -416,9 +416,6 @@
 	'Italy': {
 		'erpnext.controllers.taxes_and_totals.update_itemised_tax_data': 'erpnext.regional.italy.utils.update_itemised_tax_data',
 		'erpnext.controllers.accounts_controller.validate_regional': 'erpnext.regional.italy.utils.sales_invoice_validate',
-	},
-	'Germany': {
-		'erpnext.controllers.accounts_controller.validate_regional': 'erpnext.regional.germany.accounts_controller.validate_regional',
 	}
 }
 user_privacy_documents = [
diff --git a/erpnext/regional/germany/accounts_controller.py b/erpnext/regional/germany/accounts_controller.py
deleted file mode 100644
index 7f76493..0000000
--- a/erpnext/regional/germany/accounts_controller.py
+++ /dev/null
@@ -1,53 +0,0 @@
-import frappe
-from frappe import _
-from frappe import msgprint
-
-
-REQUIRED_FIELDS = {
-	"Sales Invoice": [
-		{
-			"field_name": "company_address",
-			"regulation": "§ 14 Abs. 4 Nr. 1 UStG"
-		},
-		{
-			"field_name": "company_tax_id",
-			"regulation": "§ 14 Abs. 4 Nr. 2 UStG"
-		},
-		{
-			"field_name": "taxes",
-			"regulation": "§ 14 Abs. 4 Nr. 8 UStG"
-		},
-		{
-			"field_name": "customer_address",
-			"regulation": "§ 14 Abs. 4 Nr. 1 UStG",
-			"condition": "base_grand_total > 250"
-		}
-	]
-}
-
-
-def validate_regional(doc):
-	"""Check if required fields for this document are present."""
-	required_fields = REQUIRED_FIELDS.get(doc.doctype)
-	if not required_fields:
-		return
-
-	meta = frappe.get_meta(doc.doctype)
-	field_map = {field.fieldname: field.label for field in meta.fields}
-
-	for field in required_fields:
-		condition = field.get("condition")
-		if condition and not frappe.safe_eval(condition, doc.as_dict()):
-			continue
-
-		field_name = field.get("field_name")
-		regulation = field.get("regulation")
-		if field_name and not doc.get(field_name):
-			missing(field_map.get(field_name), regulation)
-
-
-def missing(field_label, regulation):
-	"""Notify the user that a required field is missing."""
-	translated_msg = _('Remember to set {field_label}. It is required by {regulation}.', context='Specific for Germany. Example: Remember to set Company Tax ID. It is required by § 14 Abs. 4 Nr. 2 UStG.') # noqa: E501
-	formatted_msg = translated_msg.format(field_label=frappe.bold(_(field_label)), regulation=regulation)
-	msgprint(formatted_msg)
diff --git a/erpnext/regional/germany/test_accounts_controller.py b/erpnext/regional/germany/test_accounts_controller.py
deleted file mode 100644
index 8bd378c..0000000
--- a/erpnext/regional/germany/test_accounts_controller.py
+++ /dev/null
@@ -1,12 +0,0 @@
-import frappe
-import unittest
-from erpnext.regional.germany.accounts_controller import validate_regional
-
-
-class TestAccountsController(unittest.TestCase):
-
-	def setUp(self):
-		self.sales_invoice = frappe.get_last_doc('Sales Invoice')
-
-	def test_validate_regional(self):
-		validate_regional(self.sales_invoice)