Update Withdrawal Flow Key Screen (Building transaction data)

[SorinQ]

As Is: The current "Building Transaction Data" screen lacks detailed information, which may leave users uncertain about the status if this step takes longer than expected, especially on the mainnet.

To Be: Update the "Building Transaction Data" screen to provide users with:

• An estimated time of completion if this step takes longer on the mainnet.
• Clear, accessible information about what this step involves.
• Reassurance that the process is ongoing and nothing is broken.

https://www.figma.com/design/Ov4M1oVlSrO4Pl7NmGOHC1/%22Zero%22?node-id=58-3755&t=Y9P9w96lMLaQ5nbz-4