refactor KeyVaultSettings

Related to: #300

Author: sikutisa

src/AzureOpenAIProxy.ApiApp/Configurations/KeyVaultSettings.cs

@@ -1,4 +1,4 @@
-namespace AzureOpenAIProxy.ApiApp.Configurations;
+namespace AzureOpenAIProxy.ApiApp.Configurations;
 
 /// <summary>
 /// This represents the settings entity for Key Vault.
@@ -18,5 +18,5 @@ public class KeyVaultSettings
     /// <summary>
     /// Gets or sets the secret names.
     /// </summary>
-    public Dictionary<string, string> SecretNames { get; set; } = new();
+    public Dictionary<string, string> SecretNames { get; set; } = [];
 }