chore(capabilities): drop the unreachable duplicates in denial_reason() (#152)

The function ended with verbatim copies of two branches it had already
run. Both conditions are character-identical to the earlier ones, the
earlier ones always return, and nothing between them touches $required,
$gate, or any state either condition reads — so the copies could never
execute.

Worth deleting rather than ignoring, because the duplicate tier block is
a WORSE version of the one that runs: it omits the
saddle_insufficient_scope branch. If it ever became reachable it would
send an OAuth-scope-limited agent to raise the site's access level, which
is the wrong screen — the exact bug #108 fixed. A stale copy of a
corrected code path sitting next to the corrected one is how that comes
back.

No behaviour change and no new test: unreachable code cannot change
behaviour, and the proof nothing moved is capabilities-test.php's
existing gate-ordering coverage staying green. 612 tests, 0 lint errors.

Closes #151

Author: ifahimreza

includes/class-saddle-capabilities.php

@@ -506,25 +506,6 @@ public static function denial_reason( $ability_name ) {
 			);
 		}
 
-		if ( 'read' !== $required && '' !== $required && self::is_domain_enforced() && ! self::domain_matches_recorded() ) {
-			return array(
-				'code'    => 'saddle_domain_drift',
-				'message' => __( 'This site\'s domain changed since write access was granted, and the owner has domain enforcement on — write tools are refused until they re-confirm the access level (Saddle → Permissions). Do not retry; tell the user.', 'saddle' ),
-			);
-		}
-
-		if ( '' !== $required && ! self::tier_allows( $required ) ) {
-			return array(
-				'code'    => 'saddle_tier_denied',
-				'message' => sprintf(
-					/* translators: 1: required access level, 2: current access level. */
-					__( 'This tool needs the "%1$s" access level, but this site allows "%2$s". Only the site owner can raise it (Saddle → Permissions). Do not retry — ask the user to change the level if they want this done.', 'saddle' ),
-					$required,
-					self::get_tier()
-				),
-			);
-		}
-
 		return null;
 	}