refactor(root_config): remove redundant nil check in Init

From the Go specification:

  "3. If the map is nil, the number of iterations is 0." [1]

Therefore, an additional nil check for before the loop is unnecessary.

[1]: https://go.dev/ref/spec#For_range

Signed-off-by: Eng Zer Jun <engzerjun@gmail.com>

config/root_config.go

@@ -167,12 +167,9 @@ func (rc *RootConfig) Init() error {
 	}
 
 	// init registry
-	registries := rc.Registries
-	if registries != nil {
-		for _, reg := range registries {
-			if err := reg.Init(); err != nil {
-				return err
-			}
+	for _, reg := range rc.Registries {
+		if err := reg.Init(); err != nil {
+			return err
 		}
 	}