Make Shipping FK deliveryAgent_flightCodePersonId "on delete set null" (#270)

Author: KarlLevik

schemas/ispyb/updates/2025_04_30_Shipping_fk_personId_on_delete_set_null.sql

@@ -0,0 +1,12 @@
+INSERT IGNORE INTO SchemaStatus (scriptName, schemaStatus) VALUES ('2025_04_30_Shipping_fk_personId_on_delete_set_null.sql', 'ONGOING');
+
+ALTER TABLE Shipping
+  DROP CONSTRAINT Shipping_ibfk_4;
+
+  ALTER TABLE Shipping
+  ADD CONSTRAINT Shipping_ibfk_4
+    FOREIGN KEY (deliveryAgent_flightCodePersonId)
+      REFERENCES Person (personId)
+        ON DELETE SET NULL ON UPDATE CASCADE;
+
+UPDATE SchemaStatus SET schemaStatus = 'DONE' WHERE scriptName = '2025_04_30_Shipping_fk_personId_on_delete_set_null.sql';