ENH: raise an error if the daq has not yet been configured

[klauer]

Description

Raise an error if the daq object is not available/has not been instantiated/configured in the current session.

Motivation and Context

@vespos reported that a simple daq scan raised the following error:

>>> RE(bp.daq_ascan([], sim.fast_motor1, 920, 930, 11, events=120, record=False))
...
AttributeError: 'NoneType' object has no attribute 'parent'

This indicates to me that None is making its way into the detector list in bluesky.
Getting a confusing error like this isn't very friendly, so let's catch it early.

How Has This Been Tested?

Where Has This Been Documented?

This PR text.

Pre-merge checklist

• Code works interactively
• Code contains descriptive docstrings, including context and API
• New/changed functions and methods are covered in the test suite where possible
• Test suite passes locally
• Test suite passes on GitHub Actions
• Ran docs/pre-release-notes.sh and created a pre-release documentation page
• Pre-release docs include context, functional descriptions, and contributors as appropriate

[tangkong]

This looks good to me on the whole, I was concerned about other apps / code paths that might rely on this, but after some brief poking around I think this is appropriate

[ZLLentz]

Same thoughts as in the pcdsdaq-side PR, the original traceback without this was rough to parse