Prevent Python from importing the host's pip packages

This patch prevents Python from searching the user's installed pip
packages as well as the host's `site` package. The host's `site`
package normally performs the setup necessary to allow importing
globally installed pip packages. We don't want that.

From the upstream documentation:
https://docs.python.org/3/using/cmdline.html

    -s
        Don’t add the user site-packages directory to sys.path.
        See also PEP 370 – Per user site-packages directory

    -S
        Disable the import of the module site and the
        site-dependent manipulations of sys.path that it
        entails. Also disable these manipulations if site is
        explicitly imported later (call site.main() if you
        want them to be triggered).

Change-Id: I11a64c33920fc174dd8ac5d200e2e8550a3c084a
Signed-off-by: Philipp Schrader <philipp.schrader@gmail.com>
diff --git a/frc971/control_loops/python/BUILD b/frc971/control_loops/python/BUILD
index a4b8fb8..8679374 100644
--- a/frc971/control_loops/python/BUILD
+++ b/frc971/control_loops/python/BUILD
@@ -26,12 +26,12 @@
     ],
     data = [
         "//third_party/cddlib:_cddlib.so",
-        "@python_repo//:scipy",
     ],
     target_compatible_with = ["@platforms//cpu:x86_64"],
     deps = [
         ":python_init",
         "//external:python-glog",
+        "@python_repo//:scipy",
     ],
 )
 
@@ -98,6 +98,7 @@
     deps = [
         ":libspline",
         ":python_init",
+        "@python_repo//:numpy",
     ],
 )