Simplify code which duplicated a library function
Simplify code which duplicated a library function

Summary: I learned of this utility from Gabe while D13600021 was under review. This simplifies another place where I was catching the exception that `Sys_utils.cat` could raise.

Reviewed By: gabelevi

Differential Revision: D13613686

fbshipit-source-id: a1e0673dc918631b627296fbc51169dfb05124a0

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