Fix check/mypy for dev.env.txt virtual environment

Problem: check/mypy passes in the mypy.env.txt environment, but fails
on "unnecessary type ignore" in dev.env.txt virtual environment,
because it installs IPython with its type information.

Solution: Ignore IPython in type checks.

Author: pavoljuhas

cirq-core/cirq/contrib/svg/svg_test.py

@@ -1,5 +1,5 @@
 # pylint: disable=wrong-or-nonexistent-copyright-notice
-import IPython.display  # type: ignore
+import IPython.display
 import numpy as np
 import pytest
 

dev_tools/conf/mypy.ini

@@ -17,7 +17,7 @@ follow_imports = silent
 ignore_missing_imports = true
 
 # Non-Google
-[mypy-sympy.*,matplotlib.*,proto.*,pandas.*,scipy.*,freezegun.*,mpl_toolkits.*,networkx.*,ply.*,astroid.*,pytest.*,_pytest.*,pylint.*,setuptools.*,qiskit.*,quimb.*,pylatex.*,filelock.*,sortedcontainers.*,tqdm.*,ruamel.*,absl.*,tensorflow_docs.*,ipywidgets.*, cachetools.*]
+[mypy-IPython.*,sympy.*,matplotlib.*,proto.*,pandas.*,scipy.*,freezegun.*,mpl_toolkits.*,networkx.*,ply.*,astroid.*,pytest.*,_pytest.*,pylint.*,setuptools.*,qiskit.*,quimb.*,pylatex.*,filelock.*,sortedcontainers.*,tqdm.*,ruamel.*,absl.*,tensorflow_docs.*,ipywidgets.*,cachetools.*]
 follow_imports = silent
 ignore_missing_imports = true