Locks transformation fix in `@itwin/imodels-access-backend-tests`

[austeja-bentley]

In this PR:

• Fixed an issue where locks received from the platform code were not correctly transformed in PlatformToClientAdapter class due to incorrect iteration over a map.
• Added integration tests in @itwin/imodels-access-backend-tests package. All three lock related methods are used
  • BackendIModelsAccess.queryAllLocks
  • BackendIModelsAccess.releaseAllLocks
  • BackendIModelsAccess.acquireLocks