e2e testspec grouped actions

[williamvega]

More e2e tests have bloated the testspec proto. The tests that send/watch events could use better grouping.

Similar to how is being done in #5018, it would make sense to group the action and its parameters together, instead of the top-level action/selection combination. In the proto, the api request itself can be referenced and additional information be wrapped in a message.

In that pr, a node-scoped action went from:

action: ACTION_CANCEL
selection: SELECTION_BY_NODE
nodePoolTag: node-ops
executor: local-cluster

to:

cancelOnNode:
  nodePoolTag: node-ops
  request:
    executor: local-cluster
    queues:
      - e2e-test-queue

This pr also converts all remaining tests to use the event itself defined in pkg/api directly instead of adding more event sub-fields to the testspec proto.

Fixes #5077

[greptile-apps]

Greptile Summary

The PR groups e2e test actions with their API request parameters and updates the test runner and YAML test specifications to consume the new shapes.

• Replaces top-level action/selection fields with cancel, preempt, reprioritize, and job-set action configurations.
• Centralizes action dispatch and node-name resolution in the test runner.
• Regenerates the TestSpec protobuf bindings and migrates affected e2e test cases.

Confidence Score: 5/5

The PR appears safe to merge.

No blocking failure remains; the previously reported job-set preemption no-op is resolved by populating the request with every submitted job ID.

Important Files Changed

Filename	Overview
internal/testsuite/testrunner.go	Centralizes grouped-action detection and dispatch; the revised preemption path now supplies all submitted job IDs and resolves the prior no-op.
pkg/api/testspec.proto	Replaces the top-level action and selection model with grouped request-specific action messages.
pkg/api/testspec.pb.go	Regenerates Go protobuf types and serialization code for the new TestSpec schema.
internal/testsuite/queue/queue.go	Treats a present queue configuration without an explicit setup block as a default queue setup.
testsuite/testcases/preemption/preempt_by_ids_1x5.yaml	Migrates the multi-job preemption test to the grouped request format.

_{Reviews (11): Last reviewed commit: "Merge branch 'master' into feat/testspec..." | Re-trigger Greptile}