`fatxpool`: rotator cache size now depends on pool's limits (#7102)

# Description

This PR modifies the hard-coded size of extrinsics cache within
[`PoolRotator`](https://github.com/paritytech/polkadot-sdk/blob/cdf107de/substrate/client/transaction-pool/src/graph/rotator.rs#L36-L45)
to be inline with pool limits.

The problem was, that due to small size (comparing to number of txs in
single block) of hard coded size:

https://github.com/paritytech/polkadot-sdk/blob/cdf107de/substrate/client/transaction-pool/src/graph/rotator.rs#L34
excessive number of unnecessary verification were performed in
`prune_tags`:

https://github.com/paritytech/polkadot-sdk/blob/cdf107de

/substrate/client/transaction-pool/src/graph/pool.rs#L369-L370

This was resulting in quite long durations of `prune_tags` execution
time (which was ok for 6s, but becomes noticable for 2s blocks):
```
Pruning at HashAndNumber { number: 83, ... }. Resubmitting transactions: 6142, reverification took: 237.818955ms    
Pruning at HashAndNumber { number: 84, ... }. Resubmitting transactions: 5985, reverification took: 222.118218ms    
Pruning at HashAndNumber { number: 85, ... }. Resubmitting transactions: 5981, reverification took: 215.546847ms
```

The fix reduces the overhead:
```
Pruning at HashAndNumber { number: 92, ... }. Resubmitting transactions: 6325, reverification took: 14.728354ms    
Pruning at HashAndNumber { number: 93, ... }. Resubmitting transactions: 7030, reverification took: 23.973607ms    
Pruning at HashAndNumber { number: 94, ... }. Resubmitting transactions: 4465, reverification took: 9.532472ms    
```

## Review Notes
I decided to leave the hardocded `EXPECTED_SIZE` for the legacy
transaction pool. Removing verification of transactions during
re-submission may negatively impact the behavior of the legacy
(single-state) pool. As in long-term we probably want to deprecate old
pool, I did not invest time to assess the impact of rotator change in
behavior of the legacy pool.

---------

Co-authored-by: command-bot <>
Co-authored-by: Iulian Barbu <14218860+iulianbarbu@users.noreply.github.com>