[FIX] stock: add button to remove lines in SN detailed operations form

Currently there is an action_assign_serial_show_details button within
the detailed operations form of a serial tracked product move.
Unfortunately there is no way to undo the assigning/creating of move
lines from this action (including via clicking the "Discard" button).
This can lead to a lot of manual work (e.g. 500 SNs produced instead of
50) to remove unwanted move lines. To remedy this, we add in a button
to unlink all of the move's move lines whenever the Assign Serial
Numbers button is visible.

closes odoo/odoo#71831

Task: 2426281
X-original-commit: a6191c43001f961c20b5b4d32e1fcb218df69d17
Signed-off-by: Arnold Moyaux <amoyaux@users.noreply.github.com>

addons/stock/models/stock_move.py

@@ -656,6 +656,19 @@ class StockMove(models.Model):
         self._generate_serial_numbers()
         return self.action_show_details()
 
+    def action_clear_lines_show_details(self):
+        """ Unlink `self.move_line_ids` before returning `self.action_show_details`.
+        Useful for if a user creates too many SNs by accident via action_assign_serial_show_details
+        since there's no way to undo the action.
+        """
+        self.ensure_one()
+        if self.picking_type_id.show_reserved:
+            move_lines = self.move_line_ids
+        else:
+            move_lines = self.move_line_nosuggest_ids
+        move_lines.unlink()
+        return self.action_show_details()
+
     def action_assign_serial(self):
         """ Opens a wizard to assign SN's name on each move lines.
         """

addons/stock/views/stock_move_views.xml

@@ -165,6 +165,12 @@
                                         title="Assign Serial Numbers">
                                     <span>Assign Serial Numbers</span>
                                 </button>
+                                <button name="action_clear_lines_show_details" type="object"
+                                        class="btn-link"
+                                        title="Clear Lines"
+                                        attrs="{'invisible': [('display_assign_serial', '=', False)]}">
+                                    <span>Clear All</span>
+                                </button>
                             </div>
                         </group>
                     </group>