[ADP-3453] Soft fail wallet-e2e CI test as flaky (#4797)

This PR exclude the haskell-e2e CI (mostly an empty box) from CI
requirements to pass, by making it a soft failer.

.buildkite/pipeline.yml

@@ -117,6 +117,8 @@ steps:
 
     - label: Run Haskell E2E Tests (linux)
       command: 'nix develop --command bash -c "just e2e-local"'
+      soft_fail:
+        - exit_status: 130
       timeout_in_minutes: 5
       agents:
         system: ${linux}