Enable linters for test packages

[saima-s]

Is your feature request related to a problem? Please describe. As of now linters are disabled from test packages in .golangci.yaml file:

issues:
  exclude-rules:
    - path: '_test.go'
      linters:
        - errcheck                      # Errors may be ignored in tests.
        - unparam                       # Tests might have unused function parameters.
        - lll
        - dupl
        - misspell
        - nestif
        - gci

Describe the solution you'd like After enabling this linter, fix all kind of linter issues coming up in test packages.

[github-actions[bot]]

Thanks for opening this issue :+1:. The team will review it shortly.

If this is a bug report, make sure to include clear instructions how on to reproduce the problem with minimal reproducible examples, where possible. If this is a security report, please review our security policy as outlined in SECURITY.md.

If you haven't already, please take a moment to review our project's Code of Conduct document.