fix: remove unused import

Author: chagong

com.microsoft.java.debug.plugin/src/main/java/com/microsoft/java/debug/plugin/internal/JavaHotCodeReplaceProvider.java

@@ -81,7 +81,6 @@
 import com.sun.jdi.ThreadReference;
 import com.sun.jdi.VMDisconnectedException;
 import com.sun.jdi.VirtualMachine;
-import com.sun.jdi.request.EventRequest;
 import com.sun.jdi.request.StepRequest;
 
 import io.reactivex.Observable;