LibWeb: Implement skeleton of ECDSA sign for SubtleCrypto

Author: https://github.com/stelar7
Commit: bc2a5e24bc
Pull-request: https://github.com/SerenityOS/serenity/pull/23737
Reviewed-by: https://github.com/ADKaster ✅
Reviewed-by: https://github.com/trflynn89

Userland/Libraries/LibWeb/Crypto/SubtleCrypto.cpp

@@ -576,6 +576,7 @@ SupportedAlgorithmsMap supported_algorithms()
     define_an_algorithm<RSAOAEP, RsaOaepParams>("decrypt"_string, "RSA-OAEP"_string);
 
     // https://w3c.github.io/webcrypto/#ecdsa
+    define_an_algorithm<ECDSA, EcdsaParams>("sign"_string, "ECDSA"_string);
     define_an_algorithm<ECDSA, EcKeyGenParams>("generateKey"_string, "ECDSA"_string);
 
     return internal_object;