Until relatively recently, English keyboards didn't have accents, so accents on words imported from other languages were commonly just dropped. Now that it's easier to add them, careful writers and editors (especially those with some exposure to foreign languages) generally try to, but the anglicized spelling without the accent typically still isn't considered wrong.
As with many aspects of English usage, spelling is not formally regulated by any central authority, only by the consensus of people such as teachers, editors, commentators, and dictionary writers. The result is a spectrum as opposed to a clear line between right and wrong.
In practical terms, a determining factor is often pronunciation. Most English speakers, unlike the subset in this forum, don't speak any foreign language and will not make any effort to imitate, say, a French É or a German Ü. They don't know or care that Ç is a different sound from C. So you're probably more likely to see 'Bon appetit' without the accent than with, and you know there's a company named Uber. Even the team that Leo Messi plays for is often misspelled Barca in print (though Apple spellcheck just tried to fix it for me here).
There are some imported words, however, that have a higher chance of retaining a written accent. One example is the noun 'résumé,' which needs its accents to distinguish it from the verb 'resume.' (Though alas, spellcheck won't help you there.)
So the upshot is that any entry should probably include both forms.
I would also include a warning, if we knew how, that English speakers say 'Bon appétit' much less often than German speakers say Guten Appetit. But 'Enjoy your meal' is already in there, and I suppose there are also a bunch of archive threads.