Universal/NoUselessAliases: remove unused constant

Copy/pasta. This sniff does not record metrics.

Author: jrfnl

Universal/Sniffs/UseStatements/NoUselessAliasesSniff.php

@@ -28,15 +28,6 @@
 final class NoUselessAliasesSniff implements Sniff
 {
 
-    /**
-     * Name of the "Use import source" metric.
-     *
-     * @since 1.1.0
-     *
-     * @var string
-     */
-    const METRIC_NAME = 'Import use statement type';
-
     /**
      * Returns an array of tokens this test wants to listen for.
      *