remove legacy layout migration

src/vs/workbench/browser/layout.ts

@@ -1757,11 +1757,10 @@ export abstract class Layout extends Disposable implements IWorkbenchLayoutServi
 		const workbenchDimensions = this.getClientArea();
 		const width = this.storageService.getNumber(Storage.GRID_WIDTH, StorageScope.GLOBAL, workbenchDimensions.width);
 		const height = this.storageService.getNumber(Storage.GRID_HEIGHT, StorageScope.GLOBAL, workbenchDimensions.height);
-		// At some point, we will not fall back to old keys from legacy layout, but for now, let's migrate the keys
-		const sideBarSize = this.storageService.getNumber(Storage.SIDEBAR_SIZE, StorageScope.GLOBAL, this.storageService.getNumber('workbench.sidebar.width', StorageScope.GLOBAL, Math.min(workbenchDimensions.width / 4, 300)));
+		const sideBarSize = this.storageService.getNumber(Storage.SIDEBAR_SIZE, StorageScope.GLOBAL, Math.min(workbenchDimensions.width / 4, 300));
 		const panelDimension = positionFromString(this.storageService.get(Storage.PANEL_DIMENSION, StorageScope.GLOBAL, 'bottom'));
 		const fallbackPanelSize = this.state.panel.position === Position.BOTTOM ? workbenchDimensions.height / 3 : workbenchDimensions.width / 4;
-		const panelSize = panelDimension === this.state.panel.position ? this.storageService.getNumber(Storage.PANEL_SIZE, StorageScope.GLOBAL, this.storageService.getNumber(this.state.panel.position === Position.BOTTOM ? 'workbench.panel.height' : 'workbench.panel.width', StorageScope.GLOBAL, fallbackPanelSize)) : fallbackPanelSize;
+		const panelSize = panelDimension === this.state.panel.position ? this.storageService.getNumber(Storage.PANEL_SIZE, StorageScope.GLOBAL, fallbackPanelSize) : fallbackPanelSize;
 
 		const titleBarHeight = this.titleBarPartView.minimumHeight;
 		const statusBarHeight = this.statusBarPartView.minimumHeight;