Coding Standards: Remove unnecessary isset() check in wp_delete_term().

The top of the `foreach` loop already continues early if `$default` is not set.

Follow-up to [5533], [10813], [50389].

Props justlevine.
See #63268.

git-svn-id: https://develop.svn.wordpress.org/trunk@60332 602fd350-edb4-49c9-b593-d223f7449a82

Author: SergeyBiryukov

src/wp-includes/taxonomy.php

@@ -2143,11 +2143,11 @@ function wp_delete_term( $term, $taxonomy, $args = array() ) {
 			)
 		);
 
-		if ( 1 === count( $terms ) && isset( $default ) ) {
+		if ( 1 === count( $terms ) ) {
 			$terms = array( $default );
 		} else {
 			$terms = array_diff( $terms, array( $term ) );
-			if ( isset( $default ) && isset( $force_default ) && $force_default ) {
+			if ( isset( $force_default ) && $force_default ) {
 				$terms = array_merge( $terms, array( $default ) );
 			}
 		}