Show agent picker for Background Agents in welcome view (#298202)

* Show agent picker for Background Agents in welcome view

* Apply suggestion from @Copilot

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

---------

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

Author: DonJayamanne

src/vs/workbench/contrib/chat/browser/actions/chatExecuteActions.ts

@@ -477,9 +477,10 @@ export class OpenModePickerAction extends Action2 {
 						ContextKeyExpr.or(
 							ChatContextKeys.lockedToCodingAgent.negate(),
 							ChatContextKeys.chatSessionHasCustomAgentTarget),
-						// Hide in welcome view when session type is not local
+						// Show in welcome view for local sessions or sessions with custom agent target
 						ContextKeyExpr.or(
 							ChatContextKeys.inAgentSessionsWelcome.negate(),
+							ChatContextKeys.chatSessionHasCustomAgentTarget,
 							ChatContextKeys.agentSessionType.isEqualTo(AgentSessionProviders.Local))),
 					group: 'navigation',
 				},