Fix collection delete for collections w/ m2o to them (#5809)

* Fix new-collection relational field creation

* Fix collection delete for collections w/ m2o to them

Fixes #5793

.changeset/forty-birds-wonder.md

@@ -0,0 +1,5 @@
+---
+'directus': patch
+---
+
+Fixed issue that would prevent collections that had a relationship pointing to them from being deleted.

api/src/services/fields.ts

@@ -378,7 +378,7 @@ export class FieldsService {
 			// Cleanup directus_fields
 			const metaRow = await trx.select('id').from('directus_fields').where({ collection, field }).first();
 
-			if (metaRow.id) {
+			if (metaRow?.id) {
 				// Handle recursive FK constraints
 				await trx('directus_fields').update({ group: null }).where({ group: metaRow.id });
 			}