HAI-1814 Fix sending multiple application delete requests

[markohaarni]

Description

Fixed a problem where user could press confirm button in application cancel dialog many times in a row, which would send multiple delete requests to backend. Fixed this by putting the confirm button in loading state when clicking it first time.

Jira Issue: https://helsinkisolutionoffice.atlassian.net/browse/HAI-1814

Type of change

• Bug fix
• New feature
• Other

Instructions for testing

1. Create new cable report application, first page is enough to fill, and save it.
2. Press Cancel application button in application page
3. Open the Network tab in browser developer tools
4. Try to click the Confirm button in the delete dialog as many times as you can
5. There should only be one delete request in the Network tab

Checklist:

• I have written new tests (if applicable)
• I have ran the tests myself (if applicable)
• I have made necessary changes to the documentation, link to confluence
  or other location:

Other relevant info

Please describe here if there is e.g. some requirements for this change or
other info that the tester/user needs to know.