🔄 chore: Consolidate agent model imports across middleware and tests from rebase

- Updated imports for `createAgent` and `getAgent` to streamline access from a unified `~/models` path.
- Enhanced test files to reflect the new import structure, ensuring consistency and maintainability across the codebase.
- Improved clarity by removing redundant imports and aligning with the latest model updates.

api/server/routes/files/images.agents.test.js

@@ -10,7 +10,7 @@ const {
   ResourceType,
   PrincipalType,
 } = require('librechat-data-provider');
-const { createAgent } = require('~/models/Agent');
+const { createAgent } = require('~/models');
 
 jest.mock('~/server/services/Files/process', () => ({
   processAgentFileUpload: jest.fn().mockImplementation(async ({ res }) => {

api/server/routes/files/images.js

@@ -10,7 +10,7 @@ const {
   filterFile,
 } = require('~/server/services/Files/process');
 const { checkPermission } = require('~/server/services/PermissionService');
-const { getAgent } = require('~/models/Agent');
+const db = require('~/models');
 
 const router = express.Router();
 
@@ -29,7 +29,7 @@ router.post('/', async (req, res) => {
         req,
         res,
         metadata,
-        getAgent,
+        getAgent: db.getAgent,
         checkPermission,
       });
       if (denied) {