Drop user, organization and regulated organization prompts once 1.8.0 is released and data is migrated

[greatislander]

Is your feature request related to a problem? Please describe.

As part of #2759 some of the prompts were moved from explicit columns in the database to a schemaless attribute. The old columns can be dropped from the table after the data has been migrated to the new structure.

Describe the solution you'd like

Create a migration to drop the following columns:

• User
  • dismissed_customize_prompt_at
• Organization
  • dismissed_invite_prompt_at
• Regulated Organization
  • dismissed_invite_prompt_at

Describe alternatives you've considered

No response

Additional context

No response