fix(DX-10057): fix CI test failures in migration and seed packages

- migration.test.ts: update alias assertion to expect empty array (cm:migration alias was removed)
- seed.test.ts: mock @contentstack/cli-cm-import to cut the seed→import→audit chain
  which conflicted with the existing @contentstack/cli-utilities mock

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: cs-raj

packages/contentstack-migration/test/unit/commands/cm/stacks/migration.test.ts

@@ -122,9 +122,9 @@ describe('Migration Command', () => {
       expect(MigrationCommand.usage).to.include('migration');
     });
 
-    it('should have aliases including cm:migration', () => {
+    it('should have empty aliases array (cm:migration alias removed)', () => {
       expect(MigrationCommand.aliases).to.be.an('array');
-      expect(MigrationCommand.aliases).to.include('cm:migration');
+      expect(MigrationCommand.aliases).to.be.empty;
     });
   });
 

packages/contentstack-seed/test/commands/cm/stacks/seed.test.ts

@@ -4,6 +4,7 @@ import { isAuthenticated, configHandler, cliux } from '@contentstack/cli-utiliti
 
 // Mock dependencies
 jest.mock('../../../../src/seed/index');
+jest.mock('@contentstack/cli-cm-import', () => ({ __esModule: true, default: { run: jest.fn() } }));
 jest.mock('@contentstack/cli-utilities', () => {
   const { Flags, Command } = require('@oclif/core');
   return {