Wallets should update key/descriptor birthdates when txs older than current birthdates are found #28897
Description
Please describe the feature you'd like to see added.
Key/descriptor birthdates should be updated to match the oldest transaction involving the key/descriptor when the timestamp of that transaction is older than the key/descriptor birthdate.
Is your feature related to a problem, if so please describe it.
Users may fail to provide the correct birthdates for things that they imported, which results in the wallet storing incorrect birthdates. Since #27469, birthdates are used to determine whether a block should be scanned. Incorrect birthdates result in the reindex failing to find transactions that already exist in the wallet and subsequently marking them as inactive. While this issue is resolved by reloading the wallet, and rescanning in the worst case, it shouldn't be necessary to do either of those following a reindex.
Describe the solution you'd like
No response
Describe any alternatives you've considered
No response