Rename the "planning priority" label

Blocker

Re-name the "planning priority" label as "due date sensitive" per #6619 (closed).

Why is this change being made?

The "planning priority" label has been re-named "due date sensitive". This updates all references accordingly.

Does this MR meet the acceptance criteria?

Conformity

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

Closes #6619 (closed)