Make maximized layouts available to use in smoke tests (#3807)

Fixes issue where the maximized part layouts introduced in #3616, made
specifically for testing, were not available to be used in the tests due
to being hidden from the palette.

I was mistaken in thinking that the method
`app.workbench.quickaccess.runCommand()` used some other method of
running commands than the command palette. Hence, I hide the maximized
layouts to not clutter the user's palette.

This PR just sets the maximized layouts:
`workbench.action.fullSizedPanel`, `workbench.action.fullSizedSidebar`,
and `Maximized Auxiliary Bar Layout` to be available in the command
palette.

### QA Notes
Hopefully will make life easier for smoke test users.

src/vs/workbench/services/positronLayout/browser/layouts/maximizedPartLayouts.ts

@@ -24,7 +24,7 @@ registerAction2(class extends PositronLayoutAction {
 		super({
 			id: 'workbench.action.fullSizedSidebar',
 			label: localize2('chooseLayout.fullSizedSidebarLayout', 'Maximized Sidebar Layout'),
-			hideFromPalette: true,
+			hideFromPalette: false,
 			layoutDescriptor: makeMaximizedPartLayout(Parts.SIDEBAR_PART),
 		});
 	}
@@ -35,7 +35,7 @@ registerAction2(class extends PositronLayoutAction {
 		super({
 			id: 'workbench.action.fullSizedPanel',
 			label: localize2('chooseLayout.fullSizedPanelLayout', 'Maximized Panel Layout'),
-			hideFromPalette: true,
+			hideFromPalette: false,
 			layoutDescriptor: makeMaximizedPartLayout(Parts.PANEL_PART),
 		});
 	}
@@ -46,7 +46,7 @@ registerAction2(class extends PositronLayoutAction {
 		super({
 			id: 'workbench.action.fullSizedAuxiliaryBar',
 			label: localize2('chooseLayout.fullSizedAuxiliaryBarLayout', 'Maximized Auxiliary Bar Layout'),
-			hideFromPalette: true,
+			hideFromPalette: false,
 			layoutDescriptor: makeMaximizedPartLayout(Parts.AUXILIARYBAR_PART),
 		});
 	}