Fix showing wrong welcome view content when offline (microsoft#239365)

Only apply agent content override hack in chatwidget welcome content, not contributed welcome views
Fix microsoft/vscode-copilot#12726

Author: roblourens

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

@@ -587,7 +587,10 @@ export class ChatWidget extends Disposable implements IChatWidget {
 			const welcomePart = this._register(this.instantiationService.createInstance(
 				ChatViewWelcomePart,
 				{ ...welcomeContent, tips, },
-				{ location: this.location }
+				{
+					location: this.location,
+					isWidgetWelcomeViewContent: true
+				}
 			));
 			dom.append(this.welcomeMessageContainer, welcomePart.element);
 		}

src/vs/workbench/contrib/chat/browser/viewsWelcome/chatViewWelcomeController.ts

@@ -116,6 +116,7 @@ export interface IChatViewWelcomeContent {
 export interface IChatViewWelcomeRenderOptions {
 	firstLinkToButton?: boolean;
 	location: ChatAgentLocation;
+	isWidgetWelcomeViewContent?: boolean;
 }
 
 export class ChatViewWelcomePart extends Disposable {
@@ -146,7 +147,7 @@ export class ChatViewWelcomePart extends Disposable {
 			title.textContent = content.title;
 
 			// Preview indicator
-			if (options?.location === ChatAgentLocation.EditingSession && typeof content.message !== 'function' && chatAgentService.toolsAgentModeEnabled) {
+			if (options?.location === ChatAgentLocation.EditingSession && typeof content.message !== 'function' && chatAgentService.toolsAgentModeEnabled && options.isWidgetWelcomeViewContent) {
 				// Override welcome message for the agent. Sort of a hack, should it come from the participant? This case is different because the welcome content typically doesn't change per ChatWidget
 				const agentMessage = localize({ key: 'agentMessage', comment: ['{Locked="["}', '{Locked="]({0})"}'] }, "Ask Copilot to edit your files in [agent mode]({0}). Copilot will automatically use multiple requests to pick files to edit, run terminal commands, and iterate on errors.\n\nCopilot is powered by AI, so mistakes are possible. Review output carefully before use.", 'https://aka.ms/vscode-copilot-agent');
 				content.message = new MarkdownString(agentMessage);