Limit CRM widget work item types

The CRM (Contacts) widget for work items is currently available behind the work_items_alpha feature flag, and is present for all work item types.

CRM should be scoped to appear only for Issue type, mirroring the legacy experience. If through research or customer demand we identify a strong case for adding this as a default for other types we may consider adding those in the future; alternately this could be enabled via custom types once available.

Acceptance criteria

• Contacts widget appears only for Issue, Ticket, and Incident type
• /add_contact quick action appears only for Issue, Ticket, and Incident type
• When changing type to other types, Contacts are removed (follow existing type change patterns)