merge user product.json feature has failed when using --user-data-dir commandline.

[kendling]

Describe the bug

1. Download and extract the zip package.
2. Create the shortcut for VSCodium.exe.
3. Modify the shortcut and add --user-data-dir for it.
4. Produce user product.json from https://github.com/VSCodium/vscodium/blob/master/docs/index.md#extensions--marketplace.
5. Start it via the shortcut.
6. The instance using open-vix.org still.
7. It can merge product.json when place in %AppDATA%\VSCodium\product.json

Please confirm that this problem is VSCodium-specific

• This bug doesn't happen if I using data dir as protable user data in same folder as VSCodium.exe.

Please confirm that the issue/resolution isn't already documented

• I checked the Docs page and the Troubleshooting page and my issue is not mentioned there.

Expected behavior
VSCodium can merge it when product.json place in dir prass by --user-data-dir param.

Desktop (please complete the following information):

• OS: Windows
• Architecture: x64
• Version: 10.0.22631.3807

Additional context
I reviewed the merge-user-product.patch file in repo.
The resolveUserProduct function call getUserDataPath using {} as cliArgs param, it that the problem?