[Bug]: UserGlobal changes when editing global on a story level

[valentinpalkovic]

Describe the bug

As soon as a global value like globals: {backgrounds: {value: 'dark'}} is set on a story level, after the HMR event, the userGlobal value is set, leading to a change in the URL and in the background toolbar

Reproduction link

storybookjs/storybook-rsc-demo#20

Reproduction steps

1. Open Storybook
2. Go to a story
3. Define the background for a story
4. See the url changing and the userGlobal is set. Switching to another story will persist the global value.

Additional context

No response