Revert "Remove HHClientLinter from NON_DEFAULT_LINTERS"

This reverts commit 63cf04d.

Author: Atry

src/__Private/LintRunConfig.hack

@@ -95,6 +95,7 @@ final class LintRunConfig {
     HHAST\NoFinalMethodInFinalClassLinter::class,
     HHAST\NamespacePrivateLinter::class,
     HHAST\DontHaveTwoEmptyLinesInARowLinter::class,
+    HHAST\HHClientLinter::class,
   ];
 
   private static function getNamedLinterGroup(