Return correct error in ConfigQuery

During some testing, it was discovered that attempting to validate a
config while passing an invalid token fails with the following error:

```
$ circleci --token "invalid-token" config validate .circleci/config.yml -v
...
Error: config compilation request returned an error: %!w(<nil>)
```

The behavior would previously check if an error existed, but return a
different one. After fixing that, the error prints correctly.

config/config.go

@@ -126,7 +126,7 @@ func (c *ConfigCompiler) ConfigQuery(
 		return legacyResponse, nil
 	}
 	if originalErr != nil {
-		return nil, fmt.Errorf("config compilation request returned an error: %w", err)
+		return nil, fmt.Errorf("config compilation request returned an error: %w", originalErr)
 	}
 
 	if statusCode != 200 {