Centralize OTP dev logging in Kavenegar SMS service

Move the dev-mode OTP logging into KavenegarSmsService so consumer and
admin auth flows no longer duplicate the fallback log.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/Meezi.Admin.API/Services/AdminAuthService.cs

@@ -79,9 +79,6 @@ public class AdminAuthService : IAdminAuthService
         var otp = Random.Shared.Next(100000, 999999).ToString();
         await redis.StringSetAsync($"otp:admin:{phone}", otp, TimeSpan.FromSeconds(OtpTtlSeconds));
 
-        if (string.IsNullOrWhiteSpace(_configuration["Kavenegar:ApiKey"]))
-            _logger.LogWarning("DEV admin OTP for {Phone}: {Otp}", phone, otp);
-
         try
         {
             await _smsService.SendOtpAsync(phone, otp, cancellationToken);