Implement DPI-aware divider sizing for WorkbenchPanel split panes (zaproxy#9044)

- Replace hardcoded divider sizes with DisplayUtils.getScaledSize() calls
- Use 8px for major vertical divider (status/work panels split)
- Use 6px for minor dividers (request/response and select/work splits)
- Improves UI scaling on high-DPI displays and different screen scaling settings

Signed-off-by: Wyatt Fry <wyattfry@gmail.com>

Author: wyattfry

zap/src/main/java/org/parosproxy/paros/view/WorkbenchPanel.java

@@ -72,6 +72,7 @@
 import org.parosproxy.paros.Constant;
 import org.parosproxy.paros.extension.AbstractPanel;
 import org.parosproxy.paros.extension.option.OptionsParamView;
+import org.zaproxy.zap.utils.DisplayUtils;
 import org.zaproxy.zap.view.ComponentMaximiser;
 import org.zaproxy.zap.view.ComponentMaximiserMouseListener;
 import org.zaproxy.zap.view.TabbedPanel2;
@@ -648,7 +649,7 @@ private JSplitPane createStatusPanelsSplit() {
         splitVert.addPropertyChangeListener(
                 JSplitPane.DIVIDER_LOCATION_PROPERTY, new DividerResizedListener(DIVIDER_VERTICAL));
 
-        splitVert.setDividerSize(3);
+        splitVert.setDividerSize(DisplayUtils.getScaledSize(8));
         splitVert.setOrientation(JSplitPane.VERTICAL_SPLIT);
         splitVert.setResizeWeight(0.5D);
 
@@ -1357,7 +1358,7 @@ private void splitResponsePanelWithWorkTabbedPanel(int orientation) {
 
     private static JSplitPane createSplitPane(int orientation) {
         JSplitPane splitPane = new JSplitPane(orientation);
-        splitPane.setDividerSize(3);
+        splitPane.setDividerSize(DisplayUtils.getScaledSize(6));
         splitPane.setResizeWeight(0.5D);
         splitPane.setContinuousLayout(false);
         splitPane.setDoubleBuffered(true);