Fixed null values in settings default newsletter migration (#14638)

refs https://ghost.slack.com/archives/C02G9E68C/p1651484563907609

- When the site has an empty name, it is set to `NULL` in settings.
- The name column is not nullable in newsletters, breaking the migration in that case.
- Fixed by excluding all non-nullable columns
- Replaced JS Date object with raw SQL `CURRENT_TIMESTAMP`

core/server/data/migrations/versions/4.46/2022-04-13-13-00-add-default-newsletter.js

@@ -4,6 +4,8 @@ const logging = require('@tryghost/logging');
 const startsWith = require('lodash/startsWith');
 const {createTransactionalMigration} = require('../../utils');
 
+module.exports = createTransactionalMigration(
+    async function up(knex) {
         // This uses the default settings from core/server/data/schema/default-settings/default-settings.json
         const newsletter = {
             id: (new ObjectId()).toHexString(),
@@ -28,11 +30,9 @@ const newsletter = {
             show_header_name: false,
             title_alignment: 'center',
             title_font_category: 'sans_serif',
-    created_at: new Date()
+            created_at: knex.raw('CURRENT_TIMESTAMP')
         };
 
-module.exports = createTransactionalMigration(
-    async function up(knex) {
         // Make sure the newsletter table is empty
         const newsletters = await knex('newsletters').count('*', {as: 'total'});
 
@@ -68,6 +68,13 @@ module.exports = createTransactionalMigration(
             if (startsWith(key, 'newsletter_')) {
                 key = key.slice(11);
             }
+
+            if (value === null && ['name', 'body_font_category', 'show_badge', 'show_feature_image', 'show_header_icon', 'show_header_title', 'title_alignment', 'title_font_category'].includes(key)) {
+                // Prevent setting null to non-nullable columns
+                // Default to defaults above in that case
+                continue;
+            }
+
             if (typeof newsletter[key] === 'boolean') {
                 newsletter[key] = value === 'true';
             } else {