engineapi: Fix engine_getClientVersionV1 (#13358)

For specs:
https://github.com/ethereum/execution-apis/blob/main/src/engine/identification.md#engine_getclientversionv1

The issue earlier was in json marshalling of strings returned by CL
clients. Since Git commits are already hex, no need to further hexlify
the string.
The commit string here won't have "0x" prefix - that's contentious, but,
going by the example given in the spec.
The version string doesn't have size limits, hence extending it to what
we would be using otherwise.

---------

Co-authored-by: Giulio <[email protected]>

turbo/engineapi/engine_api_methods.go

@@ -140,17 +140,18 @@ func (e *EngineServer) GetClientVersionV1(ctx context.Context, callerVersion *en
 	if callerVersion != nil {
 		e.logger.Info("[GetClientVersionV1] Received request from" + callerVersion.String())
 	}
-	commitBytes := [4]byte{}
-	c := []byte(params.GitCommit)
-	if len(c) >= 4 {
-		copy(commitBytes[:], c[0:4])
+	commitString := params.GitCommit
+	if len(commitString) >= 8 {
+		commitString = commitString[:8]
+	} else {
+		commitString = "00000000" // shouldn't be triggered
 	}
 	result := make([]engine_types.ClientVersionV1, 1)
 	result[0] = engine_types.ClientVersionV1{
 		Code:    params.ClientCode,
 		Name:    params.ClientName,
-		Version: params.Version,
-		Commit:  commitBytes,
+		Version: params.VersionWithCommit(params.GitCommit),
+		Commit:  "0x" + commitString,
 	}
 	return result, nil
 }

turbo/engineapi/engine_types/jsonrpc.go

@@ -109,10 +109,10 @@ type GetPayloadResponse struct {
 }
 
 type ClientVersionV1 struct {
-	Code    string  `json:"code" gencodec:"required"`
-	Name    string  `json:"name" gencodec:"required"`
-	Version string  `json:"version" gencodec:"required"`
-	Commit  [4]byte `json:"commit" gencodec:"required"`
+	Code    string `json:"code" gencodec:"required"`
+	Name    string `json:"name" gencodec:"required"`
+	Version string `json:"version" gencodec:"required"`
+	Commit  string `json:"commit" gencodec:"required"`
 }
 
 func (c ClientVersionV1) String() string {