Dont wait for `initializeWithProgress` when starting the Web IDE

Description

Identified in this Slack thread:

I think the situation could be mitigated by not waiting for all of the Web IDE to initialize when activating the Web IDE.

https://gitlab.com/gitlab-org/gitlab-web-ide/-/blob/f7530df31eb7622e0c619e263bee81399af332ee/packages/vscode-extension-web-ide/src/main.ts#L199

In the Web IDE, the builtin VSCode extension waits for our building Web IDE extension to finish activating, which can take a while if the project is big and we’re waiting for all the files to load.

I’ll create an issue and we’ll try to tackle this soon 👀

Implementation plan

I think we want to just remove the await here https://gitlab.com/gitlab-org/gitlab-web-ide/-/blob/f7530df31eb7622e0c619e263bee81399af332ee/packages/vscode-extension-web-ide/src/main.ts#L199 and confirm that this doesn't cause issues.

• Is the gitlab-vscode-extension dependent on the file system actually loaded? This change would cause the gitlab-vscode-extension to activate while we're still waiting for the file system to load.
• What happens if the file system fails to load? Do we still present an error correctly?
• Is there anything else that could be dependent on the file system actually loading before we return from the Web IDE extension's activate entrypoint?