Asset import feature minor enhancement

[nihal467]

Describe the bug

• even though the location is marked mandatory, there is no validation occurring in the asset import
• once we click import post selection, the users are not given any indication that the data is processing

To Reproduce
Steps to reproduce the behavior:

1. Go to https://care.coronasafe.in/assets
2. Select facility and import asset list
3. without selecting the location click import
4. See error

Expected behavior

• add a location field validation in the asset import
• upon clicking import button, it should be giving import processing notification and a loader in the import button to show, the import is processing

Screenshots

[github-actions]

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