prepareForInline triggers storyFn deprecation warning

[bmayen]

Describe the bug

I'm testing 6.2.0 beta 10 with Angular inline support. prepareForInline uses storyFn which has been deprecated.

  | deprecated | @ | browser.js:39
  | storyFn | @ | story_store.js:660
  | _callee$ | @ | prepareForInline.js:76

To Reproduce
Steps to reproduce the behavior:

1. import { prepareForInline } from '@storybook/addon-docs/angular/inline';
2. add prepareForInline to preview.js docs config
3. Load a component story and view warning in browser console

Expected behavior
No deprecation warning

System
Environment Info:

System:
OS: macOS 10.15.7
CPU: (12) x64 Intel(R) Core(TM) i7-8850H CPU @ 2.60GHz
Binaries:
Node: 14.15.5 - ~/.nvm/versions/node/v14.15.5/bin/node
npm: 6.14.11 - ---------/node_modules/.bin/npm
Browsers:
Chrome: 88.0.4324.192
Edge: 89.0.774.45
Firefox: 80.0.1
Safari: 14.0.3
npmPackages:
@storybook/addon-a11y: ^6.2.0-beta.9 => 6.2.0-beta.10
@storybook/addon-backgrounds: ^6.2.0-beta.9 => 6.2.0-beta.10
@storybook/addon-docs: ^6.2.0-beta.9 => 6.2.0-beta.10
@storybook/addon-postcss: ^2.0.0 => 2.0.0
@storybook/addon-viewport: ^6.2.0-beta.9 => 6.2.0-beta.10
@storybook/addons: ^6.2.0-beta.9 => 6.2.0-beta.10
@storybook/angular: ^6.2.0-beta.9 => 6.2.0-beta.10

[shilman]

closing as dupe to #13074