Fix the v2 build: sign-in tests use the old InitiatorKinds namespace #2454

v2 does not build since #2450 was merged after #2449. #2449 moved InitiatorKinds from FluentCMS.Infrastructure.Audit to FluentCMS.Core.Audit, and tests/FluentCMS.IntegrationTests/Identity/SignInTests.cs from #2450 still imports only the old namespace:

tests/FluentCMS.IntegrationTests/Identity/SignInTests.cs(194,26): error CS0103: The name 'InitiatorKinds' does not exist in the current context

The CI run for the merge commit 24aec09 fails, and so does every pull request into v2, such as #2453.

Scope

• Import FluentCMS.Core.Audit in SignInTests.cs.

Out of scope

• Any other change to the sign-in or audit code.

Acceptance

• dotnet build with warnings as errors and dotnet test pass on v2 with the fix.