fix(demo): COA fixes for Mexico country (#36840)

diff --git a/erpnext/accounts/doctype/account/chart_of_accounts/verified/mx_plan_de_cuentas.json b/erpnext/accounts/doctype/account/chart_of_accounts/verified/mx_plan_de_cuentas.json
index e98c2d6..858f05c 100644
--- a/erpnext/accounts/doctype/account/chart_of_accounts/verified/mx_plan_de_cuentas.json
+++ b/erpnext/accounts/doctype/account/chart_of_accounts/verified/mx_plan_de_cuentas.json
@@ -109,8 +109,7 @@
                     }
                 }, 
                 "INVENTARIOS": {
-                    "account_type": "Stock", 
-                    "is_group": 1
+                    "account_type": "Stock"
                 }
             }, 
             "ACTIVO LARGO PLAZO": {
@@ -398,10 +397,18 @@
                         "INGRESOS POR SERVICIOS 1": {}
                     }, 
                     "VENTAS": {
-                        "VENTAS EXPORTACION": {}, 
-                        "VENTAS INMUEBLES": {}, 
-                        "VENTAS NACIONALES": {}, 
-                        "VENTAS NACIONALES AL DETAL": {}
+                        "VENTAS EXPORTACION": {
+                            "account_type": "Income Account"
+                        }, 
+                        "VENTAS INMUEBLES": {
+                            "account_type": "Income Account"
+                        }, 
+                        "VENTAS NACIONALES": {
+                            "account_type": "Income Account"
+                        }, 
+                        "VENTAS NACIONALES AL DETAL": {
+                            "account_type": "Income Account"
+                        }
                     }
                 }
             },