Cleanup dead code (#6436)

* removed dead progressbar code

* clean whitespace

Co-authored-by: Benedikt Tutzer <benedikt.tutzer@gmail.com>

src/main/java/org/jabref/gui/JabRefFrame.java

@@ -23,7 +23,6 @@
 import javafx.scene.control.Menu;
 import javafx.scene.control.MenuBar;
 import javafx.scene.control.MenuItem;
-import javafx.scene.control.ProgressBar;
 import javafx.scene.control.Separator;
 import javafx.scene.control.SeparatorMenuItem;
 import javafx.scene.control.SplitPane;
@@ -155,7 +154,6 @@ public class JabRefFrame extends BorderPane {
     private final ThemeLoader themeLoader = Globals.getThemeLoader();
     private final GlobalSearchBar globalSearchBar = new GlobalSearchBar(this, Globals.stateManager);
 
-    private final ProgressBar progressBar = new ProgressBar();
     private final FileHistoryMenu fileHistory;
 
     private final Stage mainStage;
@@ -430,8 +428,6 @@ public boolean quit() {
     }
 
     private void initLayout() {
-        setProgressBarVisible(false);
-
         setId("frame");
 
         VBox head = new VBox(createMenu(), createToolbar());
@@ -1084,21 +1080,6 @@ public FileHistoryMenu getFileHistory() {
         return fileHistory;
     }
 
-    /**
-     * Set the visibility of the progress bar in the right end of the status line at the bottom of the frame.
-     */
-    public void setProgressBarVisible(final boolean visible) {
-        progressBar.setVisible(visible);
-    }
-
-    /**
-     * Sets the indeterminate status of the progress bar.
-     * <p>
-     */
-    public void setProgressBarIndeterminate(final boolean value) {
-        progressBar.setProgress(ProgressBar.INDETERMINATE_PROGRESS);
-    }
-
     /**
      * Return a boolean, if the selected entry have file
      *