LibWeb/Fetch: Propagate OOM errors from HeaderList::extract_mime_type()

Author: https://github.com/linusg
Commit: ad4b4046f4
Pull-request: https://github.com/SerenityOS/serenity/pull/17698
Reviewed-by: https://github.com/kennethmyhra ✅

Userland/Libraries/LibWeb/Fetch/Response.h

@@ -38,7 +38,7 @@ public:
     virtual ~Response() override;
 
     // ^BodyMixin
-    virtual Optional<MimeSniff::MimeType> mime_type_impl() const override;
+    virtual ErrorOr<Optional<MimeSniff::MimeType>> mime_type_impl() const override;
     virtual Optional<Infrastructure::Body&> body_impl() override;
     virtual Optional<Infrastructure::Body const&> body_impl() const override;