fix: add multi email transport system (#2942)

packages/lib/jobs/definitions/emails/send-signing-email.handler.ts

@@ -1,4 +1,3 @@
-import { mailer } from '@documenso/email/mailer';
 import DocumentInviteEmailTemplate from '@documenso/email/templates/document-invite';
 import { isRecipientEmailValidForSending } from '@documenso/lib/utils/recipients';
 import { prisma } from '@documenso/prisma';
@@ -100,6 +99,7 @@ export const run = async ({ payload, io }: { payload: TSendSigningEmailJobDefini
     organisationId,
     claims,
     emailsDisabled,
+    emailTransport,
   } = await getEmailContext({
     emailType: 'RECIPIENT',
     source: {
@@ -215,7 +215,7 @@ export const run = async ({ payload, io }: { payload: TSendSigningEmailJobDefini
         }),
       ]);
 
-      await mailer.sendMail({
+      await emailTransport.sendMail({
         to: {
           name: recipient.name,
           address: recipient.email,