Let user remove nostr pubkey from account

app/controllers/settings_controller.rb

@@ -88,6 +88,15 @@ class SettingsController < ApplicationController
     http_status :unprocessable_entity and return
   end
 
+  # DELETE /settings/nostr_pubkey
+  def remove_nostr_pubkey
+    current_user.update! nostr_pubkey: nil
+
+    redirect_to setting_path(:experiments), flash: {
+      success: 'Public key removed from account'
+    }
+  end
+
   private
 
     def set_main_nav_section