ci: run a full lightwalletd sync from a close-to-tip zebrad

[gustavovalverde]

Motivation

On every PR push, if the zebrad state format hasn’t changed, we want to run a full lightwalletd sync from a close-to-tip zebrad, as a test. This test should take 30 minutes

Designs

• Lightwalletd updates from zebrad in less than half an hour, so that part of the test can be run on every PR change
• This approach would use already generated disks from previous stateful disk generations job https://github.com/ZcashFoundation/zebra/blob/main/.github/workflows/test.yml#L213
• A lightwalletd-test.yml might be appropriate from this point on and move specific lightwalletd tests here.

Related Work

#3922

[teor2345]

Is this the same as #3511?

[gustavovalverde]

@teor2345 I added #3511 as a dependency. Considering the test must be created (#3511) and then added to the CI (#3926)

[teor2345]

This is a high priority, because it is on the critical path, and blocking other lightwalletd integration tests.