Change order of deletion of identifiers during import.

[nithyaganeshng]

Problem:
The identifiers were deleted before making sure parsing the backup file is successful.

Solution:
Change the order of deletion of identifiers to only delete after parsing the backup file is successful.

Validation:
Verified the scenario manually.

Type of change:

• Feature work
• Bug fix
• Documentation
• Engineering change
• Test
• Logging/Telemetry

Risk:

• High – Errors could cause MAJOR regression of many scenarios. (Example: new large features or high level infrastructure changes)
• Medium – Errors could cause regression of 1 or more scenarios. (Example: somewhat complex bug fixes, small new features)
• Small – No issues are expected. (Example: Very small bug fixes, string changes, or configuration settings changes)

Work Item links:
Please include here links for this work item, or deferred work, or related work. E.g. if the refactoring is too big to fit in this PR, or the localized strings need to be updated later, please link the TODO work items here.

Documentation Links:
Please include here links to any related background documentation for this PR.