Fix failing e2e tests in test_viem_tx

[Kourin1996]

Fixes https://github.com/celo-org/celo-blockchain-planning/issues/844

This PR fixes failing e2e tests e2e_test/js-tests/test_viem_tx.mjs

Fixes made

• send overlapping nonce tx in different currencies
  • Fixes calculation of failToBumpCurrencyCap. The original calculation converted (native token fee) - 1 to the token fee value by multiplying it by numerator and dividing it by a large denominator. However, this division effectively negated the decrement operation. The new calculation make sure to get a lower fee rather than the given amount.
  • Increases timeout to 60s (It takes around 50s when running locally)
• send fee currency tx with just high enough gas price
  • Casts from BigInt to Number because chai's assert functions reject BigInt arguments for integers comparison

How to check locally

export NETWORK=alfajores
./e2e_test/run_all_tests.sh viem

[piersy]

Thanks @Kourin1996 it's great to have these tests working again!