[Blocks] - Show block variants as cards when a user clicks into a block

[bobakzahedi]

Current behavior

Clicking into a block currently navigates the user to a specific block variant

Proposed change

Show users a revised UI:

• Cards in a grid layout
• Ability to search variants (in main block)
• Ability to add a variant from the active block

Design

Design

Additional notes

[agalin920]

@bobakzahedi I think the description got cut off

[bobakzahedi]

Thanks @agalin920