[Chore] Update Nebular and Ngx-Admin to Angular 18

[rahul-rocket]

Description: Update Nebular, Ngx-Admin, and associated dependencies (including Smart Table) to Angular 18 to reduce build warnings and improve build performance.

Background:
Currently, the project is seeing numerous warning messages during builds related to Nebular and other dependencies, which may be slowing down build times. Updating to the latest versions, which are now compatible with Angular 18, should help optimize the build process. Additionally, with Ivy enabled, this upgrade should be smoother.

Implementation Steps:
Upgrade Nebular and Ngx-Admin to Angular 18:

1. Update Nebular and Ngx-Admin packages to their latest versions compatible with Angular 18.
2. Update Angular Smart Table (@angular2-smart-table or ngx-smart-table) to the latest version if available and compatible with Angular 18.
3. . Upgrade any other Angular dependencies to versions compatible with Angular 18.

Note: Ensure that all packages work well with Ivy.