Eh. I’ve seen worse at Walmart.
If anyone can wear crop tops at work, everyone can wear crop tops at work. Even the guys.
Fix your dress code.
I would have sent her home because it violates dress code. I had a new employee show up in short-shorts and a crop top, she had the body to wear this type of attire as she was an attractive women. Still I quietly told her that attire was inappropriate for the work setting, she apologized and never dressed that way again. She was a great employee it turned out, she later got her undergrad degree in computers and went on to run the network for one of the larger counties in a southern state.
I had another show up in pajamas, not appropriate, but she explained I wear these to my college classes and Walmart. That’s fine, but not to work.
I finally hand each new employee a written list of inappropriate attire and have them sign it. Sadly I have included that they must bath daily as I had one employee with such bad BO I had to ask her if she had a medical issue, no she said, then you need to start bathing daily.