cherry-pick(login): reject current login request if existing one is alive (#356)

[mittachaitu]

What this PR does / why we need it: This PR is cherry-pick of #356 and it is required to reject the login request if there is any existing connection.

Which issue this PR fixes (optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close that issue when PR gets merged): fixes #

Special notes for your reviewer:

Checklist:

• [ ] Fixes #
• [ ] Labelled this PR & related issue with documentation tag
• [ ] PR messages has document related information
• [ ] Labelled this PR & related issue with breaking-changes tag
• [ ] PR messages has breaking changes related information
• [ ] Labelled this PR & related issue with requires-upgrade tag
• [ ] PR messages has upgrade related information
• [ ] Commit has unit tests
• [ ] Commit has integration tests

Signed-off-by: mittachaitu sai.chaithanya@mayadata.io