feat: populate susbcriber in notification feed

[mocherfaoui]

What change does this PR introduce?

populate the subscriber in notification center

Why was this change needed?

closes #2404

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Legend

[jainpawan21]

@mocherfaoui
You will need to change respective DTO also

[mocherfaoui]

@jainpawan21
are you referring to this file?

novu/apps/api/src/app/widgets/dtos/message-response.dto.ts

Line 110 in d7266cd

subscriber?: SubscriberResponseDto;

[jainpawan21]

Yes

[mocherfaoui]

@jainpawan21
I think it doesn't need any change since it already includes subscriber ? correct me if I'm wrong.

[LetItRock]

hey, thank you for the contribution! 🚀
I'll give the approval if you will include the e2e test for the new subscriber field.