enable-jinja2-autoescape should not change if autoescape=select_autoescape()

[clavedeluna]

When investigating the jinja2 autoescape enabled codemod, we discovered some confusion around jinja2 docs and code. We opened a bug report for them pallets/jinja#1890

However, we don't have to wait until that is resolved. We should still not make this change

-env = Environment(autoescape=select_autoescape())
+env = Environment(autoescape=True)

We should at the very least fix this particular case, and if possible, fix any autoescape=callable_that_returns_True()