debug: take isFrameDeemphasized presentationHint from the frame if set (

#214632)

Refs discussion in #214433

src/vs/workbench/contrib/debug/common/debug.ts

@@ -547,7 +547,8 @@ export interface IStackFrame extends ITreeElement {
 }
 
 export function isFrameDeemphasized(frame: IStackFrame): boolean {
-	return frame.source.presentationHint === 'deemphasize' || frame.presentationHint === 'deemphasize' || frame.presentationHint === 'subtle';
+	const hint = frame.presentationHint ?? frame.source.presentationHint;
+	return hint === 'deemphasize' || hint === 'subtle';
 }
 
 export interface IEnablement extends ITreeElement {