Fix MachineSet replicas type: int32 instead of string

[rut31337]

Summary

• Remove quotes from replicas: "{{ item.1 | int }}" in create_new_machinesets.yml
• The quoted Jinja expression renders as a YAML string in the k8s module's definition block, causing the OCP admission webhook to reject it

Problem

When creating new MachineSets with a different instance type, the replicas field is serialized as a string ("2") instead of an integer (2). The admission webhook rejects this:

admission webhook "default.machineset.machine.openshift.io" denied the request:
json: cannot unmarshal string into Go struct field MachineSetSpec.spec.replicas of type int32

Observed on: summit-2026.lb1216-demystifying-aap-on-ocp-cluster.dev (AWS, m6a.12xlarge workers)

Test plan

• Verify MachineSet creation succeeds with the unquoted expression
• Confirm worker nodes come up with the correct instance type and count

[rut31337]

Updated the approach — simply removing quotes from the Jinja expression breaks YAML parsing (bare {{ }} is interpreted as a flow mapping).

The fix uses to_json | from_json round-trip on the definition variable. This converts the Jinja-rendered string "2" back to native integer 2 through JSON parsing, while keeping the YAML valid:

definition: >-
  {{ _machineset_def | to_json | from_json }}
vars:
  _machineset_def:
    spec:
      replicas: "{{ item.1 | int }}"

yamllint and ansible-lint (production profile) both pass locally.