don't have slot specific class attributes in the function component

[bcardarella]

Example, accordion. The documentation referes to header_class= and content_class=

Instead we should permit this:

<.accordion_set>
  <:header class="">
    DockYard StationUI Accodion
  </:header>
  <:content class="">
    Item 1
  </:content>
  <:content>
    Item 2
  </:content>
</.accordion_set>

So you can see that the slot :header and the slot :content both take the class attribute here and that is better than passing it into the top level function component. Here is how we did it for LVN:

https://github.com/liveview-native/liveview-client-swiftui/blob/main/priv/templates/lvn.swiftui.gen/core_components.ex#L614

and

https://github.com/liveview-native/liveview-client-swiftui/blob/main/priv/templates/lvn.swiftui.gen/core_components.ex#L622