Fix CMA callback

[andrea-pasquale]

CMA callback fixed by calling it for each evaluation and not for each iteartion. Should fix tests randomly failing, see #1344 for example.

Checklist:

• [x] Reviewers confirm new code works as expected.
• [x] Tests are passing.
• [x] Coverage does not decrease.
• [x] Documentation is updated.

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 99.82%. Comparing base (cb87952) to head (0858afd).

Additional details and impacted files

```diff @@ Coverage Diff @@ ## sparse_unitary #1346 +/- ## =============================================== Coverage 99.82% 99.82% =============================================== Files 72 72 Lines 10563 10572 +9 =============================================== + Hits 10544 10553 +9 Misses 19 19 ``` | [Flag](https://app.codecov.io/gh/qiboteam/qibo/pull/1346/flags?src=pr&el=flags&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=qiboteam) | Coverage Δ | | |---|---|---| | [unittests](https://app.codecov.io/gh/qiboteam/qibo/pull/1346/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=qiboteam) | `99.82% <100.00%> (+<0.01%)` | :arrow_up: | Flags with carried forward coverage won't be shown. [Click here](https://docs.codecov.io/docs/carryforward-flags?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=qiboteam#carryforward-flags-in-the-pull-request-comment) to find out more.

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