chore: remove custom logger functionality

- Remove code related to setting up and using a custom logger in OptimizelyFlutterClient.java
- Delete OptimizelyFlutterLogger.java file as it is no longer needed
- Update references to the logger channel in OptimizelyFlutterSdkPlugin.java

Author: muzahidul-opti

android/src/main/java/com/optimizely/optimizely_flutter_sdk/OptimizelyFlutterClient.java

@@ -25,7 +25,6 @@
 import com.optimizely.ab.UnknownEventTypeException;
 import com.optimizely.ab.android.event_handler.DefaultEventHandler;
 import com.optimizely.ab.android.sdk.OptimizelyClient;
-import org.slf4j.Logger;
 import java.util.HashMap;
 import java.util.Map;
 
@@ -188,14 +187,6 @@ protected void initializeOptimizely(@NonNull ArgumentsParser argumentsParser, @N
             optimizelyManagerBuilder.withVuidEnabled();
         }
 
-        // Check if custom logger is requested
-        Boolean useCustomLogger = argumentsParser.getCustomLogger();
-        Logger customLogger = null;
-        if (useCustomLogger != null && useCustomLogger) {
-            customLogger = new OptimizelyFlutterLogger("OptimizelySDK");
-            optimizelyManagerBuilder.withLogger(customLogger);
-        }
-
         OptimizelyManager optimizelyManager = optimizelyManagerBuilder.build(context);
 
         optimizelyManager.initialize(context, null, (OptimizelyClient client) -> {