fix: incorrect import causes storybook build to fail (#171033)

## Summary
[This
change](b6f20b2219/x-pack/plugins/ml/public/application/components/collapsible_panel/panel_header_items.tsx (L9))
in this PR: https://github.com/elastic/kibana/pull/167998 is causing an
error in building storybooks:
https://buildkite.com/elastic/kibana-on-merge/builds/38046#018bb9d2-7820-43ad-9144-e40d33d28c3b

In brief, the import looks like this:
```typescript
import { css } from '@emotion/react/dist/emotion-react.cjs';
```
but it should be like this:
```typescript
import { css } from '@emotion/react';
```

It looks it's a bad import, we should set up a pre-merge check for these
accidental auto-imports.

cc: @darnautov please review

x-pack/plugins/ml/public/application/components/collapsible_panel/panel_header_items.tsx

@@ -6,7 +6,7 @@
  */
 
 import { EuiFlexGroup, EuiFlexItem } from '@elastic/eui';
-import { css } from '@emotion/react/dist/emotion-react.cjs';
+import { css } from '@emotion/react';
 import React, { type FC } from 'react';
 import { useCurrentThemeVars } from '../../contexts/kibana';