refactor(common): delete unused code for HttpResource (angular#60919)

Remove the code related to exposing the response of an HTTP request as a
`Resource` itself, as the final API will not go in this direction.

PR Close angular#60919

Author: alxhub

packages/common/http/src/resource.ts

@@ -381,48 +381,3 @@ class HttpResourceImpl<T>
   // This is a type only override of the method
   declare hasValue: () => this is HttpResourceRef<Exclude<T, undefined>>;
 }
-
-/**
- * A `Resource` of the `HttpResponse` meant for use in `HttpResource` if we decide to go this route.
- *
- * TODO(alxhub): delete this if we decide we don't want it.
- */
-class HttpResponseResource implements Resource<HttpResponseBase | undefined> {
-  readonly status: Signal<ResourceStatus>;
-  readonly value: WritableSignal<HttpResponseBase | undefined>;
-  readonly error: Signal<unknown>;
-  readonly isLoading: Signal<boolean>;
-
-  constructor(
-    private parent: Resource<unknown>,
-    request: Signal<unknown>,
-  ) {
-    this.status = computed(() => {
-      // There are two kinds of errors which can occur in an HTTP request: HTTP errors or normal JS
-      // errors. Since we have a response for HTTP errors, we report `Resolved` status even if the
-      // overall request is considered to be in an Error state.
-      if (parent.status() === ResourceStatus.Error) {
-        return this.value() !== undefined ? ResourceStatus.Resolved : ResourceStatus.Error;
-      }
-      return parent.status();
-    });
-    this.error = computed(() => {
-      // Filter out HTTP errors.
-      return this.value() === undefined ? parent.error() : undefined;
-    });
-    this.value = linkedSignal({
-      source: request,
-      computation: () => undefined as HttpResponseBase | undefined,
-    });
-    this.isLoading = parent.isLoading;
-  }
-
-  hasValue(): this is Resource<HttpResponseBase> {
-    return this.value() !== undefined;
-  }
-
-  reload(): boolean {
-    // TODO: should you be able to reload this way?
-    return this.parent.reload();
-  }
-}