Enhance convert_entry_type processor to convert multiple fields in an event

Is your feature request related to a problem? Please describe.
When a given event is a list of objects with some attributes, I would like to apply convert_entry_type processor on a field in all of these objects. For example, if my event looks like below and I would like to convert all key1 attributes using convert_entry_type processor

{
 [ 
     { "key1": "value1", "key2": "value2"},
     { "key1": "value3", "key2": "value4"},
     { "key1": "value5", "key2": "value6"}
  ]
} 

Describe the solution you'd like
Similar to https://github.com/opensearch-project/data-prepper/issues/2853 having an optional "iterate-on" functionality on convert_entry_type processor will help apply the conversion on multiple fields of a given event.

Describe alternatives you've considered (Optional)
Support for providing Json Path instead of Json Pointer that points to a specific field.

Additional context
Add any other context or screenshots about the feature request here.

Start by reading the convert_entry_type processor and the related issue #2853, which describes similar iterate-on functionality. Confirm how the processor currently targets one field and define the desired behavior for the list-of-objects example. Done means an optional iterate-on capability converts the selected field in every object, with coverage for the example behavior.