Fix chat welcome view showing up (microsoft#227096)

Fix microsoft/vscode-copilot-release#1507

Author: roblourens

src/vs/workbench/contrib/chat/browser/chatViewPane.ts

@@ -115,7 +115,7 @@ export class ChatViewPane extends ViewPane {
 	}
 
 	override shouldShowWelcome(): boolean {
-		if (!this.chatAgentService.getDefaultAgent(ChatAgentLocation.Panel)) {
+		if (!this.chatAgentService.getContributedDefaultAgent(ChatAgentLocation.Panel)) {
 			return true;
 		}
 

src/vs/workbench/contrib/chat/common/chatAgents.ts

@@ -262,6 +262,7 @@ export class ChatAgentService implements IChatAgentService {
 		};
 		const entry = { data };
 		this._agents.set(id, entry);
+		this._onDidChangeAgents.fire(undefined);
 		return toDisposable(() => {
 			this._agents.delete(id);
 			if (data.isDefault) {