Fix Svelte/Vite HMR config

[felladrin]

Description

There's an issue preventing us from working with this repository out of the box using VS Code Desktop: the website enters into an endless refreshing loop. (Internal discussion)

This PR allows it to correctly work on:

• VS Code Browser, where the WebSocket port needs to be 443 due to the wss protocol.
• Desktop IDEs, where ports are automatically forwarded, and we access the website via http://localhost:<port>.

We set the fields to undefined when we don't need to overwrite them, so they will use the value from other config parameters. Here are their type definition:

HmrOptions.clientPort?: number | undefined

HmrOptions.host?: string | undefined

Note: code is the 'IDE Alias' for VS Code Browser.

How to test

1. Go to Gitpod.io Preferences, select VS Code Browser as Editor, and start a workspace using this URL: https://gitpod.io/#https://github.com/gitpod-io/website/pull/2562 - Then confirm on Network Tab if the WebSocket connection is using the Gitpod URL:
2. Go to Gitpod.io Preferences, select VS Code (Desktop) as Editor, and start a workspace using this URL: https://gitpod.io/#https://github.com/gitpod-io/website/pull/2562 - Then confirm on Network Tab if the WebSocket connection is using the localhost URL:

[adrienthebo]

I've verified this on the desktop and it works great, but I think that fixing it on the desktop might have broken the browser IDE. Doing more testing to verify this.

Edit: My default IDE is VS Code Desktop, but when I open up the VS Code browser I get the following environment variable setting: GITPOD_IDE_ALIAS=code-desktop. Because opening the same workspace in the browser and desktop have shared shell environments GITPOD_IDE_ALIAS might not provide enough information to detect the appropriate HMR configuration. 🫤

[felladrin]

I've updated the solution to avoid using environment variables. Description and instructions for testing were also updated. Could you please check again?

[adrienthebo]

Tested with vs code desktop and browser in parallel; navigating the site was extremely fast and page updates only occurred on file changes. This worked perfectly! LGTM 🚢

[akosyakov]

@felladrin it is a right solution 👍 We should do https://github.com/gitpod-io/gitpod/issues/11849 at some point to make it more reliable.