[testnet-competition] improve error message on borrowing to let user know to set as collateral

[laboon]

DESCRIPTION: I would assume that if an asset is lent, it is then available to borrow. I lent MOVR but the system shows that 0 MOVR are available to be lent out.

After attempting this, I realized that I had to set my previous assets to be used as collateral. After attempting to borrow with no collateral, an error message should be shown informing the user that they cannot borrow without having collateral.

REPRODUCTION STEPS:

1. Lend asset
2. Do not set as collateral
3. Attempt to borrow that same asset

EXPECTED BEHAVIOR: Error message informing user that they have insufficient collateral

OBSERVED BEHAVIOR: It just shows that no asset of that type available to lend, which is misleading