Search ext: Fix validation and saving on search admin screen

[colemanw]

Overview

Improves form validation and fixes saving SavedSearches in Search Kit.
Gives better user feedback, fixes bugs and improves display style.

Comments

Also fixes a possible undefined variable error in crmError function.

[civibot]

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[eileenmcnaughton]

Seems OK - will kick the tires on this work more thoroughly in the rc but this extension is still beta anyway