fixed takeScreenshot example

[dikwickley]

Fixes: #4120
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[github-actions]

Status

• ❌ No modified files found in the types directory.
  Please make sure to include types for any changes you have made. Thank you!.

[garg3133]

It should actually be require('fs/promises') instead of require('fs'): https://nodejs.org/api/fs.html#fspromiseswritefilefile-data-options

No need to add a callback.