* fix: lunchflow parity with simplefin/plaid pending behaviour
* fix: don't suggest duplicate if both entries are pending
* refactor: reuse the same external_id for re-synced pending transactions
* chore: replace illogical duplicate collision test with multiple sync test
* fix: prevent duplicates when users edit pending lunchflow transactions
* chore: add test for preventing duplicates when users edit pending lunchflow transactions
* fix: normalise extra hash keys for pending detection