Install mpmath in pip installation (pytorch#3593)

Summary:
Pull Request resolved: pytorch#3593

A followup to pytorch#2209 and pytorch#2228

Consistent with https://github.com/pytorch/executorch/blob/main/.ci/docker/requirements-ci.txt

Reviewed By: lucylq

Differential Revision: D57289472

fbshipit-source-id: e155f627fe537be85129c70da5fa91ae555b010a

Author: mergennachin

pyproject.toml

@@ -51,6 +51,7 @@ dependencies=[
   "expecttest",
   "flatbuffers",
   "hypothesis",
+  "mpmath==1.3.0",
   "numpy>=1.25.2",
   "packaging",
   "pandas",