🔧 refactor: Add and use PrincipalType Enum

- Replaced string literals for principal types ('user', 'group', 'public') with the new PrincipalType enum across various models, services, and tests for improved type safety and consistency.
- Updated permission handling in multiple files to utilize the PrincipalType enum, enhancing maintainability and reducing potential errors.
- Ensured all relevant tests reflect these changes to maintain coverage and functionality.

api/server/routes/prompts.js

@@ -6,8 +6,9 @@ const {
   SystemRoles,
   ResourceType,
   AccessRoleIds,
-  PermissionTypes,
+  PrincipalType,
   PermissionBits,
+  PermissionTypes,
 } = require('librechat-data-provider');
 const {
   makePromptProduction,
@@ -189,7 +190,7 @@ const createNewPromptGroup = async (req, res) => {
     if (result.prompt && result.prompt._id && result.prompt.groupId) {
       try {
         await grantPermission({
-          principalType: 'user',
+          principalType: PrincipalType.USER,
           principalId: req.user.id,
           resourceType: ResourceType.PROMPTGROUP,
           resourceId: result.prompt.groupId,