Applies perfsprint linter (#24999)

Replacing usages of fmt.Sprint with faster alternatives

Signed-off-by: Philippe Antoine <contact@catenacyber.fr>

server/channels/utils/hash.go

@@ -5,12 +5,12 @@ package utils
 
 import (
 	"crypto/sha256"
-	"fmt"
+	"encoding/hex"
 )
 
 func HashSha256(text string) string {
 	hash := sha256.New()
 	hash.Write([]byte(text))
 
-	return fmt.Sprintf("%x", hash.Sum(nil))
+	return hex.EncodeToString(hash.Sum(nil))
 }