[ensap] Broken due to changes on the pages logic

The module is broken due to a few small changes in the website logic, it fails with the following error:

Bug(ensap): 'listeAnneeRemuneration'
Traceback (most recent call last):
  File "/home/olivier/.local/pipx/venvs/woob/lib/python3.12/site-packages/woob/core/bcall.py", line 100, in backend_process
    for subresult in result:
                     ^^^^^^
  File "/home/olivier/.local/pipx/venvs/woob/lib/python3.12/site-packages/woob/tools/application/base.py", line 327, in _do_complete_iter
    for i, sub in enumerate(res):
                  ^^^^^^^^^^^^^^
  File "/home/olivier/sources/woob/modules/ensap/browser.py", line 69, in iter_documents
    for year in self.page.get_years():
                ^^^^^^^^^^^^^^^^^^^^^
  File "/home/olivier/sources/woob/modules/ensap/pages.py", line 47, in get_years
    return self.doc['listeAnneeRemuneration']
           ~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^
KeyError: 'listeAnneeRemuneration'

I am working on a MR for this issue.