fix: Use db_set to set a value in on_cancel
diff --git a/erpnext/assets/doctype/asset/asset.py b/erpnext/assets/doctype/asset/asset.py
index 6701810..259857f 100644
--- a/erpnext/assets/doctype/asset/asset.py
+++ b/erpnext/assets/doctype/asset/asset.py
@@ -520,7 +520,7 @@
 
 	def cancel_capitalization(self):
 		if self.capitalized_in:
-			self.capitalized_in = None
+			self.db_set("capitalized_in", None)
 			asset_capitalization = frappe.get_doc("Asset Capitalization", self.capitalized_in)
 			if asset_capitalization.docstatus == 1:
 				asset_capitalization.cancel()