Customization args normalization should be done before updation

[DubeySandeep]

1. Normalization issue:

Currently, we directly use to update the customization args for interaction and the customization args go through the normalization process in the Interaction validation stage.

What should happen instead:
A validation method is only made for validation check not for changing the data, so this issue focus on moving the normalization process from validation to the update_interaction_customization_args i.e, normalization should be done while updating the customization args.

2. Setting default value to customization args:

Currently, we use to set the default value to the customization args when the customization_args dict is empty and then validates the customization args.

What should happen instead:
Remove setting the default value to customization arg and also remove this from the to_dict conversion method of InteractionInstance class.