chore: Configure defaultChatAgent for devspaces-copilot-chat-integration

Point extensionId and chatExtensionId to
redhat.devspaces-copilot-chat-integration to prevent the chat setup
flow from trying to install GitHub.copilot-chat which is not available
in the Open VSX registry. Grant the extension trusted auth access for
github and github-enterprise providers.

Made-with: Cursor

Author: RomanNikitenko

code/product.json

@@ -110,8 +110,8 @@
 		"itemUrl": "https://open-vsx.org/vscode/item"
 	},
 	"defaultChatAgent": {
-		"extensionId": "GitHub.copilot",
-		"chatExtensionId": "GitHub.copilot-chat",
+		"extensionId": "redhat.devspaces-copilot-chat-integration",
+		"chatExtensionId": "redhat.devspaces-copilot-chat-integration",
 		"documentationUrl": "https://aka.ms/github-copilot-overview",
 		"termsStatementUrl": "https://aka.ms/github-copilot-terms-statement",
 		"privacyStatementUrl": "https://aka.ms/github-copilot-privacy-statement",
@@ -171,10 +171,12 @@
 	},
 	"trustedExtensionAuthAccess": {
 		"github": [
-			"GitHub.copilot-chat"
+			"GitHub.copilot-chat",
+			"redhat.devspaces-copilot-chat-integration"
 		],
 		"github-enterprise": [
-			"GitHub.copilot-chat"
+			"GitHub.copilot-chat",
+			"redhat.devspaces-copilot-chat-integration"
 		]
 	}
 }