[bug]: build stylex on rollup watch mode

[shaxutang]

Describe the issue

I defined a set of variables via stylex Then I build via rollup, below is my configuration dev scripts: When in rollup development mode, the style packaging is normal when building for the first time, and the defined variables can be output correctly. But when I modify the file, the variable disappears

Expected behavior

The style output in rollup watch mode contains defined variables

Steps to reproduce

1. clone https://github.com/shaxutang/sx-theme.git
2. pnpm install
3. pnpm dev
4. check the dist/esm/index.css file, the variable exists at this time
5. Modify the style content in the src/button.ts file
6. check the dist/esm/index.css file again. At this time, the variable has no output.

Test case

No response

Additional comments

No response