[BUG] NextJS addon does not get environment variables by default

Describe the bug

We use the environment variables to set up among others, API url, base url, etc. But when launching the storybook it is unable to find the setup environment variables!

To Reproduce

Just setup and NextJS project with storybook, define any page or function to use with environment variables, create its story and run it.

System

Storybook Environment Info:

  System:
    OS: Linux 6.1 Manjaro Linux
    CPU: (16) x64 AMD Ryzen 9 5900HX with Radeon Graphics
    Shell: 5.2.26 - /bin/bash
  Binaries:
    Node: 20.11.0 - ~/.nvm/versions/node/v20.11.0/bin/node
    Yarn: 1.22.21 - /usr/bin/yarn
    npm: 10.2.4 - ~/.nvm/versions/node/v20.11.0/bin/npm
    pnpm: 8.15.4 - /usr/bin/pnpm <----- active
  npmPackages:
    @storybook/addon-a11y: 7.6.17 => 7.6.17 
    @storybook/addon-essentials: 7.6.17 => 7.6.17 
    @storybook/addon-interactions: 7.6.17 => 7.6.17 
    @storybook/addon-links: 7.6.17 => 7.6.17 
    @storybook/addon-onboarding: 1.0.11 => 1.0.11 
    @storybook/addon-storysource: 7.6.17 => 7.6.17 
    @storybook/addon-themes: 7.6.17 => 7.6.17 
    @storybook/blocks: 7.6.17 => 7.6.17 
    @storybook/nextjs: 7.6.17 => 7.6.17 
    @storybook/react: 7.6.17 => 7.6.17 
    @storybook/test: 8.0.0-alpha.16 => 8.0.0-alpha.16 
    @storybook/theming: 7.6.17 => 7.6.17 
    eslint-plugin-storybook: 0.8.0 => 0.8.0 
    msw-storybook-addon: 2.0.0-beta.1 => 2.0.0-beta.1 
    storybook: 7.6.17 => 7.6.17 
    storybook-addon-pseudo-states: 2.1.2 => 2.1.2 
    storybook-addon-rtl: 1.0.0 => 1.0.0

Additional context

We are using Storybook as a workaround to test the pages with MSW, using the respective addon.

It could be fixed by applying this on the addon.