feat: update emails for self-signer (#1108)

## Description

Updated the email content based on whether the document owner is a
recipient or not.

If the document owner is a recipient (self-signer):
* the email subject will be `Please view/sign/approve your document`
* the email header will be `Please view/sign/approve your document
"<your-doc-title>"`
* the email content will be `You have initiated the document
"<your-doc-title>" that requires you to view/sign/approve it.`

Otherwise:
* the email subject will be `Please view/sign/approve this document`
* the email header will be `<doc-owner> has invited you to
view/sign/approve "<doc-title>"`
* the email content will be `<doc-owner> has invited you to
view/sign/approve the document "<doc-title>".`


## Related Issue

Related to #1091 

## Testing Performed

Tested the feature with a different number of recipients (including and
excluding the document owner - self-signer). Tested both the sending and
resending functionality.

## Checklist

- [x] I have tested these changes locally and they work as expected.
- [ ] I have added/updated tests that prove the effectiveness of these
changes.
- [ ] I have updated the documentation to reflect these changes, if
applicable.
- [x] I have followed the project's coding style guidelines.
- [ ] I have addressed the code review feedback from the previous
submission, if applicable.

## UI Screenshots

![CleanShot 2024-04-18 at 12 26
11@2x](https://github.com/documenso/documenso/assets/25515812/ca80f625-befb-4cbc-a541-f2186379d2e8)
![CleanShot 2024-04-18 at 12 27
40@2x](https://github.com/documenso/documenso/assets/25515812/8bcbb6fc-ba98-4fa1-8538-2d062febd27b)
![CleanShot 2024-04-18 at 12 27
53@2x](https://github.com/documenso/documenso/assets/25515812/25d77d98-b5ec-4270-8ffa-43774fe70526)
![CleanShot 2024-04-18 at 12 30
00@2x](https://github.com/documenso/documenso/assets/25515812/a90bb8e3-3ea8-42ff-9971-559b3e81ae6f)


<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit

## Summary by CodeRabbit

- **New Features**
- Enhanced the document invitation components to support scenarios where
the recipient is also the sender, providing customized email content and
subject lines.
- Introduced new properties in email templates to improve clarity and
relevance based on the user's role in the document signing process.

- **Refactor**
- Updated components to use a more flexible `headerContent` property for
displaying invitation headers, replacing previous individual inviter
details.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

packages/lib/server-only/document/resend-document.tsx

@@ -88,6 +88,11 @@ export const resendDocument = async ({
       const recipientEmailType = RECIPIENT_ROLE_TO_EMAIL_TYPE[recipient.role];
 
       const { email, name } = recipient;
+      const selfSigner = email === user.email;
+
+      const selfSignerCustomEmail = `You have initiated the document ${`"${document.title}"`} that requires you to ${RECIPIENT_ROLES_DESCRIPTION[
+        recipient.role
+      ].actionVerb.toLowerCase()} it.`;
 
       const customEmailTemplate = {
         'signer.name': name,
@@ -104,12 +109,20 @@ export const resendDocument = async ({
         inviterEmail: user.email,
         assetBaseUrl,
         signDocumentLink,
-        customBody: renderCustomEmailTemplate(customEmail?.message || '', customEmailTemplate),
+        customBody: renderCustomEmailTemplate(
+          selfSigner ? selfSignerCustomEmail : customEmail?.message || '',
+          customEmailTemplate,
+        ),
         role: recipient.role,
+        selfSigner,
       });
 
       const { actionVerb } = RECIPIENT_ROLES_DESCRIPTION[recipient.role];
 
+      const emailSubject = selfSigner
+        ? `Reminder: Please ${actionVerb.toLowerCase()} your document`
+        : `Reminder: Please ${actionVerb.toLowerCase()} this document`;
+
       await prisma.$transaction(
         async (tx) => {
           await mailer.sendMail({
@@ -123,7 +136,7 @@ export const resendDocument = async ({
             },
             subject: customEmail?.subject
               ? renderCustomEmailTemplate(customEmail.subject, customEmailTemplate)
-              : `Please ${actionVerb.toLowerCase()} this document`,
+              : emailSubject,
             html: render(template),
             text: render(template, { plainText: true }),
           });