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/ReadableStreamDefaultReader.cpp

@@ -152,7 +152,7 @@ private:
 JS_DEFINE_ALLOCATOR(DefaultReaderReadRequest);
 
 // https://streams.spec.whatwg.org/#default-reader-read
-WebIDL::ExceptionOr<JS::NonnullGCPtr<JS::Promise>> ReadableStreamDefaultReader::read()
+JS::NonnullGCPtr<JS::Promise> ReadableStreamDefaultReader::read()
 {
     auto& realm = this->realm();