Suggestion: remove all 'boolean' examples from storybook

[edwardhorsford]

The storybook includes 'boolean' error examples. Example:

I think all such examples should be removed. They are not part of the design system and should never be used. We would never want to present errors without error messages.

If theres's some reason they exist that I'm not aware, of I would suggest adding annotation to note they are not for regular use.

[colinrotherham]

This has been fixed in #267

Make sure error message text is added

For accessibility reasons and to align with NHS.UK frontend, the boolean error: true prop must be replaced with an error message string:

  <TextInput
    label="What is your NHS number?"
    labelProps={{ isPageHeading: true, size: 'l' }}
-   error
+   error="Enter NHS number"
  />

Read about our guidance on error messages on the design system in the NHS digital service manual.