[chore][receiver/sqlquery] Remove redundant validate function (open-t…

…elemetry#31042)

**Description:** 
[Requested change by
Dmitrii](open-telemetry#30709 (comment)),
this function was redundant as the underlying config has a `Validate`
function called automatically.

receiver/sqlqueryreceiver/config.go

@@ -17,10 +17,6 @@ type Config struct {
 	sqlquery.Config `mapstructure:",squash"`
 }
 
-func (c Config) Validate() error {
-	return nil
-}
-
 func createDefaultConfig() component.Config {
 	cfg := scraperhelper.NewDefaultScraperControllerSettings(metadata.Type)
 	cfg.CollectionInterval = 10 * time.Second