keep and upgrade unsynced ProofCollection transactions

[zeokin]

Changes

1. It makes the transaction flicker in-and-out of the mempool giving a bad user experience
2. The update part is cheap. Anyone performing a "raise" operation (ProofCollection->SingleProof) can just follow it up by an "update" operation. So the proof upgraders should keep outdated ProofCollection transactions in their mempool.

[codspeed-hq]

Merging this PR will not alter performance

✅ 5 untouched benchmarks

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_{Comparing zeokin:proof-upgrading-improvements (1cb6cc9) with master (6a04161)}