[PM-18088] Add unit test coverage for admin methods on CiphersController and CipherService (#5460)

* Add comprehensive test coverage for CipherService restore, delete, and soft delete methods

* Add comprehensive admin cipher management tests for CiphersController

* Enhance CiphersController admin methods with comprehensive test coverage

- Add tests for provider user scenarios in admin cipher management methods
- Implement tests for custom user with edit any collection permissions
- Add test coverage for RestrictProviderAccess feature flag
- Improve test scenarios for delete, soft delete, and restore operations

* Refactor CiphersControllerTests to simplify and optimize test methods

* Optimize CiphersControllerTests with code cleanup and test method improvements

* Extend CiphersControllerTests to support Admin and Owner roles

* Add test cases for custom user cipher admin operations with EditAnyCollection permission checks

- Extend CiphersControllerTests with scenarios for custom users without EditAnyCollection permission
- Add test methods to verify NotFoundException is thrown when EditAnyCollection is false
- Cover delete, soft delete, and restore operations for single and bulk cipher admin actions

* Enhance CiphersControllerTests with granular access permission scenarios

- Add test methods for admin and owner roles with specific cipher access scenarios
- Implement tests for accessing specific and unassigned ciphers
- Extend test coverage for delete, soft delete, and restore operations
- Improve test method naming for clarity and precision

* Add bulk admin cipher delete and soft delete tests for specific and unassigned ciphers

- Implement test methods for DeleteManyAdmin and PutDeleteManyAdmin
- Cover scenarios for owner and admin roles with access to specific and unassigned ciphers
- Verify correct invocation of DeleteManyAsync and SoftDeleteManyAsync methods
- Enhance test coverage for bulk cipher admin operations

Author: r-tome