Move data-testid in placeholder_reassigned_actions component

What does this MR do and why?

Previously, the data-testid was duplicated on both the GlAvatarLabeled root element and the inner img tag.

After the change in gitlab-org/gitlab-services/design.gitlab.com!5104 (merged) the data-testid appears only in the img tag,

This change moves the data-test-id to the parent element to fix the E2E test.

References

https://gitlab.com/gitlab-org/quality/e2e-test-issues/-/issues/1708

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