SearchKit - Show Pledge as a primary entity

[colemanw]

Overview

Show Pledges as a primary entity in SearchKit, since it has its own tab on the contact summary screen.

Before

Pledges buried in the "Other" list of secondary entities.

After

Pledges in the top list of searchable entities.

[civibot]

(Standard links)

• If this is your first pull-request for CiviCRM, please browse CONTRIBUTING.md for information about the development and testing processes.
• If you are reviewing this pull-request, you may wish to consult the test sites and the Review Standards (long template, short template).

[eileenmcnaughton]

Just noting that I checked that Grant is already primary & missing from your list because it is not enabled on your site, not because it is not primary