MNT: Remove code disabling Pint array fallback

This was completely removed in Pint 0.11.

conftest.py

@@ -5,7 +5,6 @@
 
 import contextlib
 import importlib
-import os
 import textwrap
 
 import matplotlib.pyplot
@@ -17,10 +16,6 @@
 import metpy.calc
 import metpy.units
 
-# Need to disable fallback before importing pint
-os.environ['PINT_ARRAY_PROTOCOL_FALLBACK'] = '0'
-import pint  # noqa: I100, E402
-
 
 def pytest_report_header():
     """Add dependency information to pytest output."""

src/metpy/__init__.py

@@ -4,12 +4,10 @@
 """Tools for reading, calculating, and plotting with weather data."""
 
 # What do we want to pull into the top-level namespace?
-import os
 import warnings
 
 # Must occur before below imports
 warnings.filterwarnings('ignore', 'numpy.dtype size changed')
-os.environ['PINT_ARRAY_PROTOCOL_FALLBACK'] = '0'
 
 from ._version import get_version  # noqa: E402
 from .xarray import *  # noqa: F401, F403, E402