Introduce label variant for tertiary and ghost button

[panch1739]

Prerequisites

• I have read the Contributing Guidelines.
• I have not leaked any internal/restricted information like screenshots, videos, code snippets, links etc.

Feature request

For the ghost and tertiary button style, we need support two label styles: body and body-bold.
This allows adapting the emphasis of the action without changing the overall visual weight of the button itself.
The default should be body-bold.

Use case

No response

[ljanner]

@panch1739 should we support the body label style for large and small buttons too? Additionally should we add the feature only for tertiary and ghost buttons - it could be confusing for consumers if it only works on certain types of buttons. Technically this is possible it's more about how we document and communicate it to consumers. I'd be in favour of allowing the body label style for all button types since the body-bold is the default anyway.

[panch1739]

@panch1739 should we support the body label style for large and small buttons too? Additionally should we add the feature only for tertiary and ghost buttons - it could be confusing for consumers if it only works on certain types of buttons. Technically this is possible it's more about how we document and communicate it to consumers. I'd be in favour of allowing the body label style for all button types since the body-bold is the default anyway.

@ljanner We should support it for all button sizes, correct.

Regarding the style, the reason why we need to introduce this variant, is to then build the content action bar and a tree select. Is not intended ever for consumers to freely choose which label style to use in the buttons...is just for our internal component construction. So, if is just easier to put it everywhere, im fine with that. It should not be used anyways by the products.