Refactor djed-sdk\src\djed\tradeUtils.js

[aniket866]

Issue

• promiseTx uses Ethers.js sendTransaction, which is incompatible with Web3.js providers.

• verifyTx checks the transaction receipt only once, causing failures on slow or congested networks.

• UI fee is incorrectly unscaled, resulting in the fee being divided twice and producing wrong values.