fix(common): add HttpParamsOptions to the public api (#35829)

The `HttpParamsOptions` was not documented or included in the public API even
though it is a constructor argument of `HttpParams` which is a part of the
public API. This commit adds the `HttpParamsOptions` into the exports, thus
making it a part of the public API.

Resolves #20276

PR Close #35829

goldens/public-api/common/http/http.d.ts

@@ -1579,6 +1579,14 @@ export declare class HttpParams {
     toString(): string;
 }
 
+export declare interface HttpParamsOptions {
+    encoder?: HttpParameterCodec;
+    fromObject?: {
+        [param: string]: string | ReadonlyArray<string>;
+    };
+    fromString?: string;
+}
+
 export declare interface HttpProgressEvent {
     loaded: number;
     total?: number;

packages/common/http/public_api.ts

@@ -12,7 +12,7 @@ export {HttpHeaders} from './src/headers';
 export {HTTP_INTERCEPTORS, HttpInterceptor} from './src/interceptor';
 export {JsonpClientBackend, JsonpInterceptor} from './src/jsonp';
 export {HttpClientJsonpModule, HttpClientModule, HttpClientXsrfModule, HttpInterceptingHandler as ɵHttpInterceptingHandler} from './src/module';
-export {HttpParameterCodec, HttpParams, HttpUrlEncodingCodec} from './src/params';
+export {HttpParameterCodec, HttpParams, HttpParamsOptions, HttpUrlEncodingCodec} from './src/params';
 export {HttpRequest} from './src/request';
 export {HttpDownloadProgressEvent, HttpErrorResponse, HttpEvent, HttpEventType, HttpHeaderResponse, HttpProgressEvent, HttpResponse, HttpResponseBase, HttpSentEvent, HttpUploadProgressEvent, HttpUserEvent} from './src/response';
 export {HttpXhrBackend, XhrFactory} from './src/xhr';