ACU: Make end_stop=True the default

[mhasself]

Description

Make end_stop=True the default, for go_to and set_boresight tasks.

Technically this is an interface change, in that default behavior is affected, and default behavior is actively used in our running schedules. But it was agreed on DAQ call that this will be seen, by any who notices, as an improvement.

Motivation and Context

After each move, it is sensible to put on the brakes. We rarely care about servoing actively on any fixed position, because we only observe while scanning. This change does not affect behavior when scanning -- elevation axis will remain in Preset mode in that case (which may or may not be what is wanted; cf #964).

How Has This Been Tested?

Tested on simulator, but this is quite a minor change in any case.

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]

Looks good!