[Optimize] Skip proposing duplicated transmissions

[raychu86]

Motivation

This PR skips adding transmissions to proposals if the transmission was included in storage. This is because if the node's proposal/certificate gets included in a subdag, it must also include the previous certificates, meaning we'd have duplicated transmission ids.

This optimization reduces state bloat in blocks and also opens more space in proposals for unique transmissions, which would allow more TPS. The second change in this PR processes more transmissions from the worker in case there were some in the initial num_transmissions_per_worker that were skipped.

This PR also increase the number of unconfirmed transmissions we pass into the memory pool. Previously it was bounded by MAX_TRANSMISSIONS_PER_BATCH, however if any of these transmissions are invalid or duplicated, then we effectively limit the theoretical throughput. We still only include MAX_TRANSMISSIONS_PER_BATCH in each proposal, however we now have a larger pool of transmissions to choose from.

TLDR - The changes are:

1. Skip transmissions that are already included in storage.
2. Increase number of transmissions sent into the mempool.

This PR needs to be validated with internal devnet testing, particularly with the mempool change.

Test Plan

A test has been added that we properly skip the transmissions that already exist in storage.

[vicsn]

Logic LGTM, makes a lot of sense

[kpandl]

Did an initial run and was able to reach around 38 TPS on an ongoing basis with credits.aleo transfer_public transactions

[howardwu]

@onetrickwolf's testing has also confirmed that block times have fallen significantly with this PR, when there are tx-cannons driving the network forward