shielding extrinsic can fail on L1 without notice in UI

This shielding attempt failed because BalanceLow, yet the UI jumped form broadcast to finalized
https://assethub-polkadot.subscan.io/extrinsic/8490062-2

Attempt was to shield 1000 USDC.e (100% of the account's balance). account has enough DOT to pay for fees. (the UI hardcodes fee payment to same asset. that's why it failed. But the shielding dialog should check for this)