LibWeb: Remove OOM propagation from Fetch::Body

Author: https://github.com/trflynn89
Commit: 3e991a55fa
Pull-request: https://github.com/SerenityOS/serenity/pull/24138

Userland/Libraries/LibWeb/Fetch/Request.cpp

@@ -47,7 +47,7 @@ void Request::visit_edges(Cell::Visitor& visitor)
 
 // https://fetch.spec.whatwg.org/#concept-body-mime-type
 // https://fetch.spec.whatwg.org/#ref-for-concept-body-mime-type%E2%91%A0
-ErrorOr<Optional<MimeSniff::MimeType>> Request::mime_type_impl() const
+Optional<MimeSniff::MimeType> Request::mime_type_impl() const
 {
     // Objects including the Body interface mixin need to define an associated MIME type algorithm which takes no arguments and returns failure or a MIME type.
     // A Request object’s MIME type is to return the result of extracting a MIME type from its request’s header list.