[BUG] Enable running `tests/io/test_user_agent.py` in `cudf.pandas` tests

[galipremsagar]

Describe the bug
Investigate hangs in tests/io/test_user_agent.py and enable running it in cudf.pandas tests.

This set of tests is being ignored here:

cudf/python/cudf/cudf/pandas/scripts/run-pandas-tests.sh

Line 25 in aab6137

PYTEST_IGNORES="--ignore=tests/io/test_user_agent.py \