fix(mail): add password_salt to plugin migration 0001

Core migration 0026/0110 tried to add password_salt to mail_accounts
but the table did not exist during core migration run. Added
password_salt directly to the mail plugin initial migration.

app/plugins/builtins/mail/migrations/0001_initial.sql

@@ -3,6 +3,7 @@
 CREATE TABLE IF NOT EXISTS mail_accounts (
     id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
     user_id UUID NOT NULL,
+    password_salt VARCHAR(64) NOT NULL DEFAULT '',
     email_address VARCHAR(255) NOT NULL,
     display_name VARCHAR(255) NOT NULL DEFAULT '',
     imap_host VARCHAR(255) NOT NULL,