[FIX] survey: consider question as normal if question selection is random

Currently in the survey:
- If we have a conditional question and the question selection mode is
  random and we select the question layout as one page with all questions
  or one page per section, the conditional question is not visible. This
  happens because the  random mode condition is ignored.
- If we have a conditional question and the question selection mode is random
  and we select the question layout as one page per section, the traceback is
  generated when we start the survey. This is because it is trying to get value
  from the "selected_answer", which does not exist in random mode.

Expected behaviour is If the question selection mode is random, the conditional
questions are considered normal and visible and do not generate a trace back if
the question layout is one page per section.

This commit fixes the above issue by adding a condition that treats
the conditional question as a normal question when the question
selection mode is random.

task-3142209

closes odoo/odoo#111171

Signed-off-by: Warnon Aurélien (awa) <awa@odoo.com>