fix: Check if plan parameter is subclass of Device

[tpoliaw]

The previous check for whether a parameter was a bluesky device (and
would therefore go via the string-to-device lookup) was based on the
type being an instance of one of the bluesky protocols.

isinstance(param_type, BLUESKY_PROTOCOLS)

For types, isinstance returns True if the type being compared to is a
protocol that is implemented but False if it is a class that is
extended.

This means that for a device that only extends Device, this check would
return False and the device could not be injected.

Including a check for the type being a subclass of Device allows all
device subclasses to be looked up.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 95.15%. Comparing base (d0803d1) to head (0a67ad3).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #1368   +/-   ##
=======================================
  Coverage   95.15%   95.15%           
=======================================
  Files          43       43           
  Lines        3016     3016           
=======================================
  Hits         2870     2870           
  Misses        146      146           

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