Either way is fine.

Student or Learner
iPhone's Siri recognizes both [ˈpraɡmədəst] and [ˈpraɡmətist] and spells out "pragmatist" correctly.
The question is: Do you readily accept both pronunciations? Or do you prefer one to another? Obviously, if you don't know how to spell the word, pronouncing [ˈpraɡmətist] will help.
pragmatist
[ˈpraɡmədəst]
NOUN
a person who is guided more by practical considerations than by ideals.
"hardheaded pragmatists firmly rooted in the real world"
Either way is fine.
I am not a teacher.
For me, only the version with "t" is acceptable.