[antithesis] Enable reuse of banff e2e test for antithesis testing

[marun]

Why this should be merged

Having to duplicate existing test coverage to benefit from execution with antithesis is not ideal. Better to be able to trivially refactor compatible e2e coverage for reuse. This PR refactors the banff e2e test for reuse with antithesis to demonstrate that this is possible.

How this works

• adds new APITestFunction type that a compatible e2e test can implement to allow for execution with both ginkgo and antithesis
• adds ExecuteAPITest helper to simplify execution of an APITestFunction with ginkgo
• Refactors the banff e2e test into an APITestFunction executed by ExecuteAPITest
• Refactors the avalanchego antithesis test setup to support execution of the banff test
  • Moves test dispatch into a new function so that panics can be recovered via a deferred function
    • This supports use of require by e2e tests without risking an unhandled panic exiting the test process

How this was tested

CI

TODO

• Ensure banff test is actually compatible with the funding provided by the antithesis workload
  • i.e. https://github.com/ava-labs/avalanchego/actions/runs/11919591309/job/33219631694?pr=3554#step:5:134

Need to be documented in RELEASES.md?

N/A

[marun]

Switched to draft in light of wanting to rebase on #3557