Remove unused ExpandableComposite styling in IDEApplication

Neither ChooseWorkspaceDialog nor ChooseWorkspaceWithSettingsDialog
use ExpandableComposite, so the early dark-theme styling branch in
applyStylesRecursive is dead code.

Drop the ExpandableComposite handling, the import, and the
org.eclipse.ui.forms bundle dependency, which is no longer needed.

Author: vogella

bundles/org.eclipse.ui.ide.application/META-INF/MANIFEST.MF

@@ -18,7 +18,6 @@ Require-Bundle: org.eclipse.ui.ide;bundle-version="[3.21.0,4.0.0)",
  org.eclipse.e4.core.di.extensions,
  org.eclipse.e4.core.services;bundle-version="2.4.0",
  org.eclipse.e4.core.contexts;bundle-version="[1.12.0,2.0.0)",
- org.eclipse.ui.forms,
  org.eclipse.urischeme;bundle-version="[1.3.0,2.0.0)",
  org.eclipse.e4.ui.di
 Export-Package: org.eclipse.ui.internal.ide.application;x-internal:=true,

bundles/org.eclipse.ui.ide.application/src/org/eclipse/ui/internal/ide/application/IDEApplication.java

@@ -66,7 +66,6 @@
 import org.eclipse.swt.widgets.Shell;
 import org.eclipse.ui.IWorkbench;
 import org.eclipse.ui.PlatformUI;
-import org.eclipse.ui.forms.widgets.ExpandableComposite;
 import org.eclipse.ui.internal.Workbench;
 import org.eclipse.ui.internal.WorkbenchPlugin;
 import org.eclipse.ui.internal.WorkspaceLock;
@@ -953,11 +952,6 @@ private void applyStylesRecursive(Control control, Color bg, Color fg, Color lin
 
 		}
 
-		if (control instanceof ExpandableComposite expandable) {
-			expandable.setTitleBarForeground(fg);
-			expandable.setToggleColor(fg);
-			expandable.setActiveToggleColor(fg);
-		}
 		if (control instanceof Composite composite) {
 			for (Control child : composite.getChildren()) {
 				applyStylesRecursive(child, bg, fg, linkColor);