change(tests): Adds timeouts tonic clients in tests

[arya2]

Motivation

The test_grpc_methods_mocked seemed to hang in CI here: https://github.com/ZcashFoundation/zebra/actions/runs/10101606903/job/27935542667?pr=8694#step:12:2915

Tonic doesn't add any timeout by default on the server or the client, the test isn't checking for panics in the spawned tokio tasks for handling mock service responses, and the mock service isn't wrapped in a Timeout tower layer.

Solution

• Adds a 2s timeout to the tonic client endpoints in the affected tests
• Increases the timeout of the relevant mock services from the 300ms default to 2s

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]

Looks good.

The base branch was changed.