Getting a comment for discussion returns an internal server error

[Chief-Rishab]

Describe the bug
After creating a comment for a discussion and a call on GetAllComments or GetComment APIs is giving an internal server error with logs that the owner's email is NULL and cant be converted to string.

Server logs:

ERRO[0173] error getting list of comments: sql: Scan error on column index 7, name "owner.email": converting NULL to string is unsupported  ref=1677205983
ERRO[0173] finished unary call with code Internal        error="rpc error: code = Internal desc = Internal Server Error - ref (1677205983)" grpc.code=Internal grpc.method=GetAllComments grpc.service=odpf.compass.v1beta1.CompassService grpc.start_time="2023-02-24T08:03:03+05:30" grpc.time_ms=2.061 peer.address="127.0.0.1:48390" span.kind=server system=grpc

To Reproduce
Steps to reproduce the behavior:
1.Create a comment for a discussion
2. Get all comments or Get the comment by id

Expected behavior
Should return the comment body