fix(add-money): stop pushing Coinbase email verification twice

[bmc08gt]

The email verification screen is pushed twice when adding money via Coinbase / Google Pay.

Root cause

Picking Coinbase from the add-money deposit sheet emits one _selections value that two handlers act on, and both navigate to verification:

1. InternalPurchaseMethodController.presentDepositOptions runs its own email/phone gate and returns AppRoute.Verification → navigate.
2. SwapViewModel's persistent purchaseMethodController.selections collector — its Coinbase branch ran the email gate and dispatched OnVerificationNeeded (a second navigation) before bailing on the missing purchaseAmount.

The deposit-sheet selection is PaymentAction.Plain with no amount; the real purchase carries an amount. The collector was reacting to a selection it shouldn't handle — the same "shared controller also emits for the deposit sheet" trap the currency-creator already guards against.

Fix

• SwapViewModel — move the purchaseAmount ?: return bail to the top of the Coinbase branch, before the email gate. The collector now ignores the amount-less deposit-sheet selection, leaving presentDepositOptions as the sole handler → one push.
• InternalPurchaseMethodController — resolve the email the same way as CoinbaseOnRampController.resolveEmail() (verified email only when the flag is on, any entered email otherwise). The pre-emptive gate previously forced verification whenever the flag was on — even for an already-verified user — and disagreed with the purchase-time check.