Import escape function directly from markupsafe (#9858)

Adds a direct dependency on markupsafe, instead of relying on the
implicit dependency via Flask.

This is in preparation of Flask 3.0 support, which will drop compat for
importing escape indirectly.

docker/main/requirements-wheels.txt

@@ -1,6 +1,7 @@
 click == 8.1.*
 Flask == 2.3.*
 imutils == 0.5.*
+markupsafe == 2.1.*
 matplotlib == 3.7.*
 mypy == 1.6.1
 numpy == 1.23.*