[Cashtab] Remove unused deps

Summary:
Depends on D15246

Remove dependencies no longer used in Cashtab

bc-bip68 - must have been accidentally added while testing lock time
lodash.isempty - was once used with bch-api utxo org methods, should have been deleted when chronik implemented
lodash.isequal - same
long - used when chronik first introduced and numbers were of this type
prompts - probably from original create react app before it was ejected
, lodash.isempty, lodash.isequal, long, tailwindscss, and prompts

Test Plan:
npm run build
grep -r --exclude-dir={node_modules,build,coverage} 'bc-bip68' and no output
grep -r --exclude-dir={node_modules,build,coverage} 'lodash.isempty' and no output
grep -r --exclude-dir={node_modules,build,coverage} 'lodash.isequal' and no output
grep -r --exclude-dir={node_modules,build,coverage} 'long' and no output
grep -r --exclude-dir={node_modules,build,coverage} 'prompts' and no output

Reviewers: #bitcoin_abc, Fabien

Reviewed By: #bitcoin_abc, Fabien

Subscribers: Fabien

Differential Revision: https://reviews.bitcoinabc.org/D15247