Check if sensor list is changing and adjust.

[msilvafe]

Fixes #927

Description

Checks if sensor list has changed (due to deactivating or activating slots) and if so re-grabs the list of desired sensors to query.

Motivation and Context

See #927

How Has This Been Tested?

Hasn't been tested, needs testing on site.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.

[BrianJKoopman]

I remember we discussed this in person before I went to site. I think where we ended up was that this needs to be split into separate blocks, since the block structure can't change once published.

The 372 agent is one example of having different blocks per field. Also see the ocs docs on message format.