testing: adopt optional value standard

For #124362

src/vs/workbench/api/common/extHostTypeConverters.ts

@@ -1728,6 +1728,8 @@ export namespace TestItem {
 
 	export function toPlain(item: ITestItem): Omit<vscode.TestItem, 'children' | 'invalidate' | 'discoverChildren'> {
 		return {
+			parent: undefined,
+			error: undefined,
 			id: TestId.fromString(item.extId).localId,
 			label: item.label,
 			uri: URI.revive(item.uri),

src/vs/workbench/api/common/extHostTypes.ts

@@ -3328,9 +3328,9 @@ export enum TestRunProfileKind {
 @es5ClassCompat
 export class TestRunRequest implements vscode.TestRunRequest {
 	constructor(
-		public readonly include?: vscode.TestItem[],
-		public readonly exclude?: vscode.TestItem[] | undefined,
-		public readonly profile?: vscode.TestRunProfile,
+		public readonly include: vscode.TestItem[] | undefined = undefined,
+		public readonly exclude: vscode.TestItem[] | undefined = undefined,
+		public readonly profile: vscode.TestRunProfile | undefined = undefined,
 	) { }
 }