Need a UI message when an extension fails to initialize

<!-- ⚠️⚠️ Do Not Delete This! feature_request_template ⚠️⚠️ --> <!-- Please read our Rules of Conduct: https://opensource.microsoft.com/codeofconduct/ --> <!-- Please search existing issues to avoid creating duplicates. --> <!-- Describe the feature you'd like. --> Currently if the `activate()` extension function throw an exception, the VS Code behavior in reporting this error is different depending on whether the extension is in the retail or development environment. Here is the code line that produces the error message upon activation failure: https://github.com/microsoft/vscode/blob/b547b58db642cac86c6a869cd025713f4e2cac9f/src/vs/workbench/api/browser/mainThreadExtensionService.ts#L107 In the development environment, a UI message is displayed, while in retail mode the message is recorded to the Development Tools Console.   This makes it difficult to troubleshoot for customers, as they don't normally have the Development Tools Console opened, and the user experience is as if the extension has been activated but doesn't do anything. Please consider unifying the experience by always displaying the UI message. A sample extension (with only one line `throw new Error('Inducing activation failure')` is attached. [sample_extension.zip](https://github.com/microsoft/vscode/files/11193949/sample_extension.zip)