fix(data): type overloaded add for is optimistic true | undefined (#2906)

TypeScript only recognizes the overloads as method signatures when being overloaded not the actual implementation, added overload for the case where isOptimistic is true or undefined (default for entity).

This will allow for the following:

`.add(entityWithoutId, { isOptimistic: false })`
`.add(entityWithId, { isOptimistic: true })`
`.add(entityWithId, { // any other options without whatever settings and no explicit value for isOptimistic })`
`.add(entityWithId)`

Author: yharaskrik

modules/data/src/entity-services/entity-collection-service-base.ts

@@ -143,7 +143,11 @@ export class EntityCollectionServiceBase<
    */
   add(
     entity: Partial<T>,
-    options: Omit<EntityActionOptions, 'isOptimistic'> & { isOptimistic: true }
+    options: EntityActionOptions & { isOptimistic: false }
+  ): Observable<T>;
+  add(
+    entity: T,
+    options?: EntityActionOptions & { isOptimistic?: true }
   ): Observable<T>;
   add(entity: T, options?: EntityActionOptions): Observable<T> {
     return this.dispatcher.add(entity, options);