Cancel button navigation issue in pools

When you are navigating in a subpool (you are at least in 2nd depth level), hitting the cancel button sends you to the pool list (root level) instead of the father of that subpool (1st depth level).

Please, follow the screenshots to better understand the issue (error1.png -> error2.png -> error3.png -> error4.png).

To fix the issue, the whole cancel behaviour in question pool's section has been changed so there are some more tests to do.
Here is the tests list:

From a 2nd depth level pool or deeper:
1. Create a new question. Then try to copy, move or delete the question and then click on the cancel button. You must return to the current pool.
2. Try to create a new sub-pool then click on the cancel button and check it returns to the current pool.
3. Click on the cancel button and check it returns to the parent pool.

From a 3rd depth level pool:
1. Click on the breadcrumb's parent pool (2nd depth level pool) and from the parent pool click on the cancel button to get the 1st level pool.