fix: handle withoutEnlargement for undefined height or width

[Zhousiru]

What?

This patch implements the functionality in imageResizer to omit the generation of the image when either width or height is undefined and withoutEnlargement is set to undefined

Why?

#9986: withoutEnlargement doesn't work when height is undefined in upload.imageSizes

How?

This code checks if withoutEnlargement is undefined and either targetWidth or targetHeight is missing. If so, it further checks whether the target dimensions (if provided) are larger than the original image dimensions. If the target would enlarge the image, it returns 'omit', skipping the resizing to prevent enlargement

Fixes #9986