Refactor Asset Model Export Formatting

[Ashesh3]

This PR introduces minor changes to the formatting of asset export fields in the Asset model. The modifications aim to enhance readability and data comprehension.

Changes include:

1. Renaming the status field from "Working Status" to "Status".
2. Modifying the current_location field to current_location__name to reflect the "Current Location Name".
3. Changing the is_working field from "Is Working" to "Working Status".
4. Removal of the warranty_details field from the export.
5. Addition of a lambda function to the CSV_MAKE_PRETTY dictionary for the is_working field to display "WORKING" or "NOT WORKING" based on the field's boolean value.

@coronasafe/care-backend-maintainers @coronasafe/care-backend-admins

[nihal467]

LGTM tested through tunnel