Ensure compatible version of numpy in isolated_notebook_test.py (#6038)

Keep numpy version in the isolated Python environment at 1.23
as numpy-1.24 is incompatible with cirq and numba.

Fixes stuck notebook tests which import numba.

Related to #5967

dev_tools/notebooks/isolated_notebook_test.py

@@ -104,6 +104,8 @@
     # https://github.com/networkx/networkx/issues/4718 pinned networkx 2.5.1 to 4.4.2
     # however, jupyter brings in 5.0.6
     'decorator<5',
+    # TODO(#5967): allow numpy-1.24 when it is supported in Cirq and numba
+    'numpy>=1.16,<1.24',
 ]