Addon Outline: Fix additional outline border in docs mode

[g-cappai]

Closes #21328

What I did

I changed the selector used to target elements to be outlined.
Now every descendant of the direct child of the ZoomElement component is outlined according to its type.

How to test

See issue -> to reproduce.

Checklist

• Make sure your changes are tested (stories and/or unit, integration, or end-to-end tests)
• Make sure to add/update documentation regarding your changes
• If you are deprecating/removing a feature, make sure to update
  MIGRATION.MD

Maintainers

• If this PR should be tested against many or all sandboxes,
  make sure to add the ci:merged or ci:daily GH label to it.
• Make sure this PR contains one of the labels below.

["cleanup", "BREAKING CHANGE", "feature request", "bug", "documentation", "maintenance", "dependencies", "other"]

[yannbf]

Hey @g-cappai thanks a lot for your contribution! I think we should make some slight changes to make this more reliable.

What about we add a data-story-block="true" to the Story block, and then we target that selector instead?

[g-cappai]

Hi @yannbf , I totally agree. Now it looks definitely better.

[yannbf]

This looks great, thank you so much for working through the feedback!

cc @JReinhold in case you want to take a look at this

[JReinhold]

@yannbf I'm sorry I'm late to the party here, but given that the story block already has a unique class "sb-story", couldn't we have used that as a selector? Looks like it would effectively do the same thing as what we do with the data attribute.

[yannbf]

@yannbf I'm sorry I'm late to the party here, but given that the story block already has a unique class "sb-story", couldn't we have used that as a selector? Looks like it would effectively do the same thing as what we do with the data attribute.

In my perspective the data attribute is safer because the classname could be changed in the future and the person might not realize its connection to the addon outline, that's why I suggested it! Also feels more descriptive than a sb-story class