fix more codacy errors. Some of them had been in from the beginning, but codacy didn't mention all

Author: Joe Wegner

app/src/cc/arduino/contributions/ContributionsSelfCheck.java

@@ -36,7 +36,6 @@
 import cc.arduino.contributions.packages.filters.UpdatablePlatformPredicate;
 import cc.arduino.view.NotificationPopup;
 import org.apache.logging.log4j.LogManager;
-import org.apache.logging.log4j.Logger;
 import processing.app.*;
 
 import javax.swing.*;

app/src/cc/arduino/view/NotificationPopup.java

@@ -50,8 +50,6 @@
 import javax.swing.event.HyperlinkListener;
 
 import cc.arduino.Constants;
-import org.apache.logging.log4j.LogManager;
-import org.apache.logging.log4j.Logger;
 import processing.app.PreferencesData;
 import processing.app.Theme;