Reject transactions for already spent coins (#2935)

## Description

Our e2e tests were flaky, example:
https://github.com/FuelLabs/fuel-core/actions/runs/14343235447/job/40207476637

The reason was that during transaction reconciliation(after we fixed
that), we included transactions that had already been executed and
confirmed in the pending pool. After the timeout on the pending pool we
will remove all dependent transactions, and in the case of the test, it
was a transaction from another test suite that used `Change`
output(which already was confirmed and existed on the chain) of the
transaction from the first test suite.

So basically, the e2e tests revealed that it was possible to submit
transactions with already spent inputs, which will be included in the
pending pool and later discarded along with all dependent
transactions(even if outputs already were stored on the chain as coins).

This change rejects transactions immediately, if they use spent coins.
TxPool has a `SpentInptus` LRU cache, storing all spent coins.

## Checklist
- [x] New behavior is reflected in tests

### Before requesting review
- [x] I have reviewed the code myself