LibWeb: Remove exceptional return types from infallible stream IDL

Author: https://github.com/trflynn89
Commit: 2d4d16ac37
Pull-request: https://github.com/SerenityOS/serenity/pull/24165
Reviewed-by: https://github.com/kennethmyhra ✅
Reviewed-by: https://github.com/shannonbooth ✅

Userland/Libraries/LibWeb/Streams/ReadableStream.cpp

@@ -83,7 +83,7 @@ bool ReadableStream::locked() const
 }
 
 // https://streams.spec.whatwg.org/#rs-cancel
-WebIDL::ExceptionOr<JS::GCPtr<JS::Object>> ReadableStream::cancel(JS::Value reason)
+JS::NonnullGCPtr<JS::Object> ReadableStream::cancel(JS::Value reason)
 {
     auto& realm = this->realm();
 
@@ -134,7 +134,7 @@ WebIDL::ExceptionOr<JS::NonnullGCPtr<ReadableStream>> ReadableStream::pipe_throu
     return JS::NonnullGCPtr { *transform.readable };
 }
 
-WebIDL::ExceptionOr<JS::NonnullGCPtr<JS::Object>> ReadableStream::pipe_to(WritableStream& destination, StreamPipeOptions const& options)
+JS::NonnullGCPtr<JS::Object> ReadableStream::pipe_to(WritableStream& destination, StreamPipeOptions const& options)
 {
     auto& realm = this->realm();