BUGFIX: fix errors during site:import

This adjusts the annotation to work with Flow 8.3.13  ... before the type with spaces was interpreted as `mixed` and caused the following error during site:import.

```
During the import of the "Sites.xml" from the package "Neos.Demo" an exception occurred: Error: During import an exception occurred: "Could not convert target type "Neos\Media\Domain\Model\ImageVariant": Could not convert target type "Neos\Media\Domain\Model\Adjustment\CropImageAdjustment", at property path "aspectRatio": Could not find a suitable type converter for "mixed" because the class / interface "mixed" does not exist."., see log for further information.
```

Resolves: neos#5448

Neos.Media/Classes/Domain/Model/Adjustment/CropImageAdjustment.php

@@ -161,10 +161,8 @@ public function getY(): ?int
 
     /**
      * This setter accepts strings in order to make configuration / mapping of settings easier.
-     *
-     * @param AspectRatio | string | null $aspectRatio
      */
-    public function setAspectRatio($aspectRatio = null): void
+    public function setAspectRatio(AspectRatio|string|null $aspectRatio = null): void
     {
         if ($aspectRatio === null) {
             $this->aspectRatioAsString = null;