Revert "Face gravity"

This reverts commit 3830a79.

Author: timkelty

src/ImageTransformer.php

@@ -93,17 +93,12 @@ private function buildTransformParams(ImageTransform $imageTransform): array
         ])->whereNotNull()->all();
     }
 
-    private function getGravityValue(ImageTransform $imageTransform): null|array|string
+    private function getGravityValue(ImageTransform $imageTransform): ?array
     {
         if ($this->asset->getHasFocalPoint()) {
             return $this->asset->getFocalPoint();
         }
 
-
-        if ($imageTransform->position === 'face' || $imageTransform->position[0] === 'face') {
-            return 'face';
-        }
-
         if ($imageTransform->position === 'center-center') {
             return null;
         }