fix: deduplicate custom array id fields (#13064)

When adding a custom ID field to an array's config, both the default
field provided by Payload, and the custom ID field, exist in the
resulting config. This can lead to problems when the looking up the
field's config, where either one or the other will be returned.

Fixes #12978

test/fields/payload-types.ts

@@ -355,6 +355,12 @@ export interface ArrayField {
         id?: string | null;
       }[]
     | null;
+  arrayWithCustomID?:
+    | {
+        id?: string | null;
+        text?: string | null;
+      }[]
+    | null;
   updatedAt: string;
   createdAt: string;
 }
@@ -1977,6 +1983,12 @@ export interface ArrayFieldsSelect<T extends boolean = true> {
         text?: T;
         id?: T;
       };
+  arrayWithCustomID?:
+    | T
+    | {
+        id?: T;
+        text?: T;
+      };
   updatedAt?: T;
   createdAt?: T;
 }