Attempt to spend unavailable coins causes app to crash
Monero wallet.
When trying to construct transaction with unavailable coins the app crashes right before final payment confirmation

Steps to reproduce the behavior:
1. Go to send
2. Put a valid address and amount exceeding the available coin amount
3. See the app crush just before the final payment confirmation

Platform:
 - OS: Android 11 RP1A.200720.011
 - Device: Redmin Note 8 Pro
 - Cake Wallet Version: 4.15.4


