REF: FD010

Is your feature request related to a problem? Please describe.
As a participatory process admin sometimes I need to delete all the current participants to upload some new set of them.

Describe the solution you'd like
To have the option to "Delete current private participants" when uploading the CSV file. This option will delete previous private participants (ie is the same process as going one by one to delete all the participants)

NOTE: even though the screenshot has a checkbox after seeing it with fresh eyes I think the UX should be the same as the other places where we have CSV files, the "Organization census". It should be like the "Delete all census data" in Admin -> Participants -> Verifications -> Census. After uploading a census you have this button:

Describe alternatives you've considered
To have a bulk action (like we have on Proposals) to delete

Additional context
This should also work for Assemblies and other spaces.

Does this issue could impact on users private data?
Yes, it's about private participants.

Acceptance criteria

• As a participatory process admin when I upload a new CSV for Private Participants I have the option to delete the already uploaded participants
• When I do this action I see a confirmation modal