Support $ index notation in Validation matcher

[SamTolmay]

Describe the bug

We currently do not support $ index notation in the Validate action matching rules. So this does not work as expected:

id: validate
type: Validate
params: items_list.$.name

Workaround

id: validate
type: Validate
params:
  _nunjucks:
    template: items_list.{{ index }}.name
    on:
      index:
        _index: 0

Lowdefy Version

v3.22.0