Lineitem alerts not displayed scoped to org unit

To quote Sharon Herbert of Sitka:

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Instead of scoping to the owning org unit, line item alerts are visible to all org units. This especially
causes a problem when multiple libraries have created the same line item alerts and cannot tell which
one belongs to their org unit.

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I can address this issue myself.

For reference, lineitem alerts are embodied by rows in acq.lineitem_note where the alert_text column is not null and refers to a row in acq.lineitem_alert_text. That latter table has an owning_lib column that we can use for scoping.

The controlled vocabulary of acq lineitem alert text is set up in an interface labeled "Line Item Alerts" in the staff client admin menu. In the PO and selection list interfaces (where alerts can be applied), we will limit the user to selecting alerts from those owned at the user's workstation org unit (or its ancestors).

When we display applied alerts, we can also display the shortname of the org unit at which the alert text is defined (the owning_lib column). This should help clarify what's going on with alerts that have already been applied using alert text from another org unit.