Update stage_galvo.py

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 50.00000% with 4 lines in your changes are missing coverage. Please review.

Project coverage is 52.53%. Comparing base (488d2b4) to head (8d14916).

Files	Patch %	Lines
src/navigate/model/devices/stages/stage_galvo.py	50.00%	4 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## develop #876 +/- ## =========================================== - Coverage 52.53% 52.53% -0.01% =========================================== Files 164 164 Lines 18455 18459 +4 =========================================== + Hits 9695 9697 +2 - Misses 8760 8762 +2 ``` | [Flag](https://app.codecov.io/gh/TheDeanLab/navigate/pull/876/flags?src=pr&el=flags&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=TheDeanLab) | Coverage Δ | | |---|---|---| | [unittests](https://app.codecov.io/gh/TheDeanLab/navigate/pull/876/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=TheDeanLab) | `52.53% <50.00%> (-0.01%)` | :arrow_down: | 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=TheDeanLab#carryforward-flags-in-the-pull-request-comment) to find out more.

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