[FIX] sale_promotion_discount_in_field: apply code

when Promo code used, promotion was not added to Applied Promo Program
of current order.

sale_promotion_discount_in_field/wizard/__init__.py

@@ -0,0 +1 @@
+from . import sale_coupon_apply_code

sale_promotion_discount_in_field/wizard/sale_coupon_apply_code.py

@@ -0,0 +1,27 @@
+from odoo import models
+from odoo.osv import expression
+
+
+class SaleCouponApplyCode(models.TransientModel):
+    _inherit = "sale.coupon.apply.code"
+
+    def apply_coupon(self, order, coupon_code):
+        # OVERRIDE to apply the program to the order without reward lines
+        error_status = {}
+        program_domain = order._get_coupon_program_domain()
+        program_domain = expression.AND(
+            [program_domain, [("promo_code", "=", coupon_code)]]
+        )
+        program = self.env["coupon.program"].search(program_domain)
+        if (
+            program
+            and program.reward_type == "discount_line"
+            and program.promo_applicability != "on_next_order"
+        ):
+            error_status = program._check_promo_code(order, coupon_code)
+            if not error_status:
+                order._create_reward_line(program)
+                order.code_promo_program_id = program
+        else:
+            return super().apply_coupon(order, coupon_code)
+        return error_status