wallet: fix importdescriptors batch abort on timestamp error #35185

Fixes #35181.

importdescriptors returns one result per request, but timestamp parsing happened before the per-item result was created. A missing or invalid timestamp could therefore throw a top-level RPC error and abort the batch response after earlier requests may already have been applied.

Handle timestamp failures per item by adding a {success: false, error: ...} result for the failing request and continuing with later requests.

Store parsed timestamps during the import loop so the rescan error path does not need to parse failed requests again.

Tested:

python3 build/test/functional/test_runner.py wallet_importdescriptors.py --timeout-factor=3

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Conflicts

Reviewers, this pull request conflicts with the following ones:

• #34861 (wallet: Add importdescriptors interface by polespinasa)
• #33392 (wallet, rpc: add UTXO set check and incremental rescan to importdescriptors by musaHaruna)
• #31668 (Added rescan option for import descriptors by saikiran57)

If you consider this pull request important, please also help to review the conflicting pull requests. Ideally, start with the one that should be merged first.

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cACK

Will review the code soon. I think this change makes sense. @achow101 is there a reason why we would want to throw and not store the error on each import?

Apart from that, there is a PR refactoring the importdescriptors code in #34861. I think it may make sense for you to try to add this patch on top of that new code. Or even maybe, if this gets a few concept ACKs I can cherry-pick your commit and add the changes in the refactor.

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🚧 At least one of the CI tasks failed. _{Task iwyu: https://github.com/bitcoin/bitcoin/actions/runs/25184385086/job/73872950325} _{LLM reason (✨ experimental): CI failed because the IWYU (include-what-you-use) check reported an incorrect/missing include in src/util/feefrac.h and exited with failure.}

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