Preserve minReplicas: null on no-op scaling edits

[Copilot]

Editing scaling range without changing values was mutating Container App config by converting minReplicas from null to 0. This PR prevents no-op scaling edits from writing changes and preserves null-vs-explicit-zero semantics.

• No-op change detection in scaling update path

  • Added explicit guard logic to skip execution when entered min/max equals current min/max.
  • Prevents unnecessary draft/template writes for unchanged scaling ranges.

• Null preservation for unchanged minimum replicas

  • Captures whether original scale.minReplicas was null in edit context.
  • During update, avoids writing minReplicas when the original value was null and min was not changed.

• Focused unit coverage for behavior

  • Added tests around:
    • no-op range updates not executing
    • changed ranges executing
    • preserving null minimum when unchanged

if (!shouldPreserveNullMinReplicas(context)) {
    this.revisionDraftTemplate.scale.minReplicas = context.newMinRange;
}

public shouldExecute(context: T): boolean {
    return shouldUpdateScaleRange(context);
}