test: add Solana delta ingress witnessing test to bouncer

[albert-llimos]

Checklist

Please conduct a thorough self-review before opening the PR.

• [x] I am confident that the code works.
• [x] I have written sufficient tests.
• [x] I have written and tested required migrations.
• [x] I have updated documentation where appropriate.

Summary

Added test for Solana delta ingress witnessing. The test is failing at the moment, as expected: https://github.com/chainflip-io/chainflip-backend/actions/runs/10401446608/job/28804557637 When this is fixed with the new pallet in PR #5060 we can add it as part of the bouncer tests.

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 71%. Comparing base (a716d50) to head (4c511dd). Report is 7 commits behind head on main.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #5155 +/- ## ====================================== Coverage 71% 71% ====================================== Files 460 453 -7 Lines 81919 81372 -547 Branches 81919 81372 -547 ====================================== - Hits 58422 58106 -316 + Misses 20404 20167 -237 - Partials 3093 3099 +6 ```

:umbrella: View full report in Codecov by Sentry.
:loudspeaker: Have feedback on the report? Share it here.