[KATC/IndexedDB] Adjust strict mode for opening leveldb-backed indexeddb

[RebeccaMahany]

Previously, we were using strict mode StrictAll:

const StrictAll = StrictManifest | StrictJournalChecksum | StrictJournal | StrictBlockChecksum | StrictCompaction | StrictReader | StrictRecovery

Several of these options prevent the database from being opened at all if corruption is present. It is more reasonable for our usecase to at least attempt to read the data out of the database. I have therefore opted to swap to StrictRecovery only (If present then leveldb.Recover will drop corrupted 'sorted table').