chore: fix reponse messages

[Kiran-pande-30]

Fixes #4786

Describe the changes you have made in this PR -

1. Better and more user useful response messages after adding members and mentors in a group

Screenshots of the changes (If any) -

Note: Please check Allow edits from maintainers. if you would like us to assist in the PR.

[qlty-cloud-legacy[bot]]

Code Climate has analyzed commit d17f8608 and detected 1 issue on this pull request.

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Category	Count
Complexity	1

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