fix: allow nullable values again

Closes: ngneat#119
Angular 18 requires TS 5.4+ which breaks the NonNullable type:
microsoft/TypeScript#56644
This reintroduces issue ngneat#81.
This commit replaces NonNullable with Exclude to allow correct typing of
ExtractRefProp and fix the issue where opening dialogs containing
undefined values throws TS2769 when trying to set the data property.

Author: jacobg213

libs/dialog/src/lib/types.ts

@@ -59,10 +59,11 @@ export type JustProps<T extends object> = Pick<
   }[keyof T]
 >;
 
-export type ExtractRefProp<T> = NonNullable<
+export type ExtractRefProp<T> = Exclude<
   {
     [P in keyof T]: T[P] extends DialogRef ? P : never;
-  }[keyof T]
+  }[keyof T],
+  undefined | null
 >;
 
 export type ExtractData<T> = ExtractRefProp<T> extends never