[python-pytrakt] Tests: Print urls for what mock data is missing

[glensc]

This makes it easy to understand if some mock data is missing:

Missing mock for GET https://api-v2launch.trakt.tv/shows/game-of-thrones/progress/collection
Missing mock for GET https://api-v2launch.trakt.tv/shows/game-of-thrones/progress/watched

[glensc]

I used print, as if I used logger then I could not see where that got logged. and even the print result is visible if I run the test from PyCharm, If I run from the terminal I get nothing.

[glensc]

From pytest docs, it should just work?

• https://docs.pytest.org/en/6.2.x/logging.html

[glensc]

Carried to my fork:

• https://github.com/glensc/python-pytrakt/commit/f82cfcc61aa7dc49609fd4040c94851c815025c7