fix: handle JSON format in render_not_found

[mroderick]

This is a fix for https://app.rollbar.com/a/codebar-production/fix/item/codebar-production/668#detail.

ActionView::MissingTemplate: Missing template errors/not_found with {locale: [:en], formats: [:json], variants: [], handlers: [:raw, :erb, :html, :builder, :ruby, :haml]}.

Searched in:
  * "/app/app/views"
  * "/app/vendor/bundle/ruby/3.4.0/gems/turbo-rails-2.0.23/app/views"
  * "/app/vendor/bundle/ruby/3.4.0/gems/actiontext-8.1.2/app/views"
  * "/app/vendor/bundle/ruby/3.4.0/gems/actionmailbox-8.1.2/app/views"

block in ApplicationController#render_not_found(/app/app/controllers/application_controller.rb:33)
    render template: 'errors/not_found', layout: false, status: :not_found
ApplicationController#render_not_found(/app/app/controllers/application_controller.rb:33)
    render template: 'errors/not_found', layout: false, status: :not_found

Summary

• Fixes MissingTemplate error in production when requests come with JSON format
• Reverts render_not_found to use respond_to block, matching the pattern in the exception handler

Root Cause

Commit 3eeca62 simplified render_not_found to only render an HTML template, but didn't handle non-HTML formats.

[olleolleolle]

LGTM!