workboards: Initialize $other_assignees array
Reverts the revert of !1 (merged) and initializes $other_assignee to avoid blowing up when there aren't multiple assignees on the workboard.
Bug: T329974 Bug: T332234
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Reverts the revert of !1 (merged) and initializes $other_assignee to avoid blowing up when there aren't multiple assignees on the workboard.
Bug: T329974 Bug: T332234