debug: fix closeReadonlyTabsOnEnd not working (microsoft#203500)

The input itself is not readonly, the filesystem is, so this check
was always failing.

The entire `debug` scheme is readonly, so we don't need to try to
replace the check with anything else. This is pretty safe since this
code path is only hit when the new setting is enabled.

Closes microsoft#197949

Author: connor4312

src/vs/workbench/contrib/debug/browser/debugService.ts

@@ -710,10 +710,7 @@ export class DebugService implements IDebugService {
 
 			if (this.configurationService.getValue<IDebugConfiguration>('debug').closeReadonlyTabsOnEnd) {
 				const editorsToClose = this.editorService.getEditors(EditorsOrder.SEQUENTIAL).filter(({ editor }) => {
-					if (editor.resource?.scheme === DEBUG_SCHEME) {
-						return editor.isReadonly() && session.getId() === Source.getEncodedDebugData(editor.resource).sessionId;
-					}
-					return false;
+					return editor.resource?.scheme === DEBUG_SCHEME && session.getId() === Source.getEncodedDebugData(editor.resource).sessionId;
 				});
 				this.editorService.closeEditors(editorsToClose);
 			}