- involves changes in csf-tools to define a flag that tells us there is (or not) a default export
- involves changes in affected packages now that loadMainConfig is async
Following #20698, [some users reported an error thrown around Magic String's `update` method](https://github.com/storybookjs/storybook/pull/20698#issuecomment-1408389425).
## What I did
It turns out the `update` method was introduced in [version `0.26.6`](https://github.com/Rich-Harris/magic-string/blob/master/CHANGELOG.md#0266-2022-10-05), but Storybook packages [actually set it to `^0.26.1`](https://github.com/storybookjs/storybook/blob/next/code/lib/builder-vite/package.json#L62).
I've opted for 0.27.0 instead of 0.26.6 because it does not seem to have any breaking changes and we could benefit from performance improvements they made.
## How to test
This should be pretty straight-forward. I think the issue does not occur on clean installs because it should already pick `magic-string`'s latest patch. Let's see if CI passes!
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