backend/hardware-controller: ISO isn't saved correctly in the metadata

[ethanjli]

Describe the bug
The Python hardware controller saves the camera's image gain (multiplied by 100) as the acq_camera_iso metadata value (resulting in a number like 346 as the ISO which is propagated into EcoTaxa object metadata), instead of saving the ISO setting the user had set in the GUI.

Expected behavior
The acq_camera_iso metadata field's value should correspond exactly to the ISO setting the user had set in the GUI, rounded to the nearest integer.

Additional context
This bug was probably introduced by PlanktoScope/device-backend#48 and integrated into the OS by #467 for prerelease in v2024.0.0-beta.2. I noticed this bug while @fabienlombard was screensharing an EcoTaxa project and looking at the metadata of an object.

[ethanjli]

We discussed this bug in the 2025-02-06 software meeting. I tentatively decided that I will publish a v2024.0.1 bugfix release for this problem as an updated OS image, as there are probably many people who haven't yet upgraded to v2024.0.0 - so they can just instead skip directly to v2024.0.1

[ethanjli]

Because of the issues encountered in #549 which were discussed in the 2025-04-02 software meeting, we decided that we will instead not publish a v2024.0.1 hotfix release and instead fast-track v2025.0.0 as the first release with the fix for the issue.