fix strict null check

src/vs/workbench/services/label/common/labelService.ts

@@ -87,7 +87,7 @@ class ResourceLabelFormattersHandler implements IWorkbenchContribution {
 				this.formattersDisposables.set(formatter, labelService.registerFormatter(formatter));
 			}));
 			delta.removed.forEach(removed => removed.value.forEach(formatter => {
-				this.formattersDisposables.get(formatter).dispose();
+				this.formattersDisposables.get(formatter)!.dispose();
 			}));
 		});
 	}