Updated paths in test_align_to_ping_time_glider_azfp to use pytest fixture

[oftfrfbf]

This is my first time commiting so I hope I am following all the right procedures.

I noticed a broken test here:

https://github.com/OSOceanAcoustics/echopype/blob/249952c8a0979063b5193197c72bdc84f5574016/echopype/tests/utils/test_align.py#L239

The file paths were not using the pytest.fixture and so the "xmlmap.root" value was ending up referenced as:

'/Users/user/Documents/github/echopype/echopype/tests/utils/echopype/test_data/azfp/rutgers_glider_external_nc/18011107.XML'

when it should be:

'/Users/user/Documents/github/echopype/echopype/test_data/azfp/rutgers_glider_external_nc/18011107.XML'

Please let me know if this isn't correct. Regards.