Skip filtering by domain if iid is given

What does this MR do?

We recently add functionality to filter alerts by domain. Alert Mutators and selectors are using same finder and they are by default scoped to operations domain. In order to make an update we need to find the alert first however since we are returning alerts scoped to operations by default from finder we fail to update alerts for threat_monitoring domain.

This MR fixes that problem by skipping filtering by domain if iid is given. (iid is given only for update)

Does this MR meet the acceptance criteria?

Conformity

• Documentation (if required)
• Code review guidelines
• Style guides

Availability and Testing

• Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.
• Tested in all supported browsers
• Informed Infrastructure department of a default or new setting change, if applicable per definition of done

Security

If this MR contains changes to processing or storing of credentials or tokens, authorization and authentication methods and other items described in the security review guidelines:

• Label as security and @ mention @gitlab-com/gl-security/appsec
• The MR includes necessary changes to maintain consistency between UI, API, email, or other methods
• Security reports checked/validated by a reviewer from the AppSec team