fix: adding guard condition for empty notification list in notify fun…

[utsav14nov]

…ction

[Gadigeppa-J]

lgtm

[rahmatrhd]

we might have missed a logic to filter the list of notification payload (notification) based on expression https://github.com/goto/guardian/pull/182/files#diff-e9d4420e58365047a594e01257c7cb0163b2856c897c1b71d125d188d8b18873R34-R43

what supposed to be done is:

1. NotifyManager holds information of multiple client e.g. slack and lark
2. NotifyManager.Notify accepts []notification and it is responsible to send notif to multiple clients according to the configured expression in each client
3. in this case, we need to pass only []notification that fulfilled the expression evaluation to the (client.Notify)

[utsav14nov]

Got it. That’s what is my concern.

But Guard condition in this MR changes still needed as it was breaking at "email": notification[0].User when []notification length is 0

Here, Expression expects email from : "email": notification[0].User i.e. from first notification in []notification list.
But this should check this criteria for email in each notification in []notification list.
So IMO, https://github.com/goto/guardian/pull/182/files#diff-e9d4420e58365047a594e01257c7cb0163b2856c897c1b71d125d188d8b18873L32-L48
should also be wrapped inside loop iterating over []notification and client.Notify(ctx, notification) call should be called with single notification each time.