Apply fix from .NET 10 analyzer

Author: bart-vmware

src/Configuration/src/ConfigServer/ConfigServerConfigurationProvider.cs

@@ -830,11 +830,8 @@ public void Dispose()
         _refreshTimer?.Dispose();
         _refreshTimer = null;
 
-        if (_timerTickLock != null)
-        {
-            _timerTickLock.Dispose();
-            _timerTickLock = null;
-        }
+        _timerTickLock?.Dispose();
+        _timerTickLock = null;
 
         if (_ownsHttpClientHandler)
         {