Resolve Rails/StrongParams TODOs for admin/dashboard/explore controllers

Problem

Several top-level, admin, dashboard and explore controllers read request params directly (params[:x], params.merge, in-place params[...] =), bypassing StrongParameters

Re: Resolve StrongParams rubocop TODOs for admin, d... (#602236 - closed)

Changes

Replaced direct params access with scoped params.permit(...) across:

• acme_challenges_controller.rb
• banzai/uploads_controller.rb
• chaos_controller.rb
• external_redirect/external_redirect_controller.rb
• health_controller.rb
• help_controller.rb
• ide_controller.rb
• invites_controller.rb
• jwt_controller.rb
• google_api/authorizations_controller.rb
• explore/catalog_controller.rb
• dashboard/snippets_controller.rb
• dashboard_controller.rb
• dashboard/projects_controller.rb
• explore/projects_controller.rb
• mailgun/webhooks_controller.rb
• admin/application_settings_controller.rb
• graphql_controller.rb

Removed the 18 fixed files from .rubocop_todo/rails/strong_params.yml.

Closes: #602236 (closed)