Checkstyle fix ConnectionStringUnitTest (#1475)

Author: rozza

driver-core/src/test/unit/com/mongodb/ConnectionStringUnitTest.java

@@ -19,7 +19,6 @@
 import com.mongodb.connection.ServerMonitoringMode;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.params.ParameterizedTest;
-import org.junit.jupiter.params.provider.MethodSource;
 import org.junit.jupiter.params.provider.ValueSource;
 
 import java.io.UnsupportedEncodingException;