Clarify what to do with ticket priority when we wait from the customer for a long time

Why is this change being made?

This change is being made because scenario mentioned in the title is not covered in the handbook at the moment.

Does this MR meet the acceptance criteria?

Assign to DRI

• Did you assign this change to the correct DRI of the page or information you are changing?

Conformity

• Added description to this MR explaining the reasons for the proposed change, per say-why-not-just-what