Remove offsets_off() method from Zurich class

[Jacfomg]

Not needed anymore

Checklist:

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

[codecov[bot]]

Codecov Report

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

Comparison is base (d123db5) 65.06% compared to head (a414f57) 65.10%.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #811 +/- ## ========================================== + Coverage 65.06% 65.10% +0.03% ========================================== Files 50 50 Lines 6032 6027 -5 ========================================== - Hits 3925 3924 -1 + Misses 2107 2103 -4 ``` | [Flag](https://app.codecov.io/gh/qiboteam/qibolab/pull/811/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/qibolab/pull/811/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=qiboteam) | `65.10% <ø> (+0.03%)` | :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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[alecandido]

Why was it needed in the first place? (and now not any longer)

[Jacfomg]

Some people asked for the sweetspots to be switched off after each execution due to temperature concerns, however this is not recommended due to the flux spikes it would generate among other matters.

Also, it allows me to build a setup without the HDAWG https://github.com/qiboteam/qibolab_platforms_qrc/pull/121 as it was hardcoded there.