Extract the magic step-timeout durations into named constants

[sshdopey]

Context

Deposit and withdraw hardcode setTimeout(..., 2200) and 2000 for the simulated pending step with no named meaning.

Scope

• Name these durations as constants so the simulated timing is explicit.

Acceptance criteria

• The simulated step delays are named constants.

Pointers

src/screens/Deposit.tsx, src/screens/Withdraw.tsx.

[forexlord]

@forexlord has applied to work on this issue as part of the Stellar Wave Program's 6th wave.

Hi maintainer, please i would love to work on this

ℹ️ Repo Maintainers: To accept this application, review their application or assign @forexlord to this issue.