[Cashtab] Re-enable send for 9-decimal tokens

Summary: Backend issue resulting in 'rounded' tokenQty utxos for 9 decimal SLPA tokens has been identified and corrected; this diff re-enables send for such tokens

Test Plan: npm start and verify that "send" button is no longer disabled for 9-decimal SLPA tokens

Reviewers: #bitcoin_abc, majcosta

Reviewed By: #bitcoin_abc, majcosta

Differential Revision: https://reviews.bitcoinabc.org/D9439