fix: resolve client delete issue

[Harshbhama]

Description

Unable to delete client despite absence of invoices or quotes #1025

Related Issues

Unable to delete client despite absence of invoices or quotes #1025

Steps to Test

• Create a new user
• Create a client attached to that user, make sure that user is not associated with any invoice.
• Try deleting user. It must be get delete now.
• Try adding client with user associated with some invoice, try deleting client, it mustn't get delete.

Screenshots (if applicable)

N/A

Checklist

• I have tested these changes
• I have updated the relevant documentation
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the codebase
• My changes generate no new warnings or errors
• The title of my pull request is clear and descriptive