If you had upgraded from Windows 7 to 10 properly, then it should be there.
Otherwise, you may give a try to by opening C:\Windows\System32\ and see if there is any stick.exe file exists there.
This site https://www.winosbite.com/stikynot-exe/ mentioned that the sticky.exe should be under system32 directory. Check the print screen.
So, my guess is, if there is already a sticky notes there in system32 folder then you may try to open and check if there is any text/backup there.
Best of luck!