fix(test): Updates ignored failure messages in lightwalletd_integration test

[arya2]

Motivation

The error returned by the getblockchaininfo RPC method was updated in #8769 for consistency, but now the lightwalletd_integration test frequently fails because the expected failure message isn't ignored.

Solution

• Updates the ignored failure message.

Related changes:

• Updates an error conversion to use the .ok_or_server_error() method

Tests

The lightwalletd_integration test should pass for this PR. (https://github.com/ZcashFoundation/zebra/actions/runs/10478114195/job/29021273807?pr=8784)

PR Author's Checklist

• The PR name will make sense to users.
• The PR provides a CHANGELOG summary.
• The solution is tested.
• The documentation is up to date.
• The PR has a priority label.

PR Reviewer's Checklist

• The PR Author's checklist is complete.
• The PR resolves the issue.

[oxarbitrage]

Can you post links to the failures ? Thanks!

[arya2]

These are the failures I noticed:
https://github.com/ZcashFoundation/zebra/actions/runs/10477542588/job/29019426390#step:16:332
https://github.com/ZcashFoundation/zebra/actions/runs/10425482865/job/28876904337#step:16:340
https://github.com/ZcashFoundation/zebra/actions/runs/10474972269/job/29011275609#step:4:363

[oxarbitrage]

Awesome, thanks!