[ Product Block Editor ] Create variations block with empty state

[louwie17]

Description:

This issue is part of #36286 epic.

When a product doesn't have any global or local attributes with the "Used for variations" enabled we should show an empty state with an action button to allow users to "add variation options".
This issue will only focus on creating the initial variations block and the empty state. The "add variation options" can be disabled for now until that functionality has been added.

Design

AkVNGImLgSqCObTQ3idVn7-fi-1637_204904

Acceptance criteria

• Have the variations block rendered within the Variations tab (see [Product Block Editor] Add Variations Tab #38880 )
• If an existing product has 0 local or global attributes with "Used for variations" enabled, display the Options empty state with the "add variation options"
• If an existing product has local or global attributes with "Used for variations" enabled we should render the InnerBlocks

[louwie17]

You can use display: none to hide the inner blocks, so that they are still being rendered within the React tree.