Hi,
As per the official documentation, Adobe flash player is not a requirement for the Exchange server. It could be installed if you have enabled RDSH (Remote desktop session host) or browsers (edge/chrome) etc
https://learn.microsoft.com/en-us/exchange/plan-and-deploy/prerequisites?view=exchserver-2016
https://learn.microsoft.com/en-us/exchange/plan-and-deploy/system-requirements?view=exchserver-2016
Also, it looks like that it’s no longer supported.
https://www.adobe.com/mena_en/products/flashplayer/end-of-life.html
You can uninstall using DISM command, refer https://www.saotn.org/how-to-uninstall-and-remove-adobe-flash-player-in-windows-server/
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