Install (#3593)

Summary:

A followup to #2209

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

Differential Revision: D57289472

Author: mergennachin

pyproject.toml

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