Refactor Keithley 2600 driver to use ParameterWithSetpoints for fast sweep

[trlemon]

WIP

Summary of Changes

• Remove dependence on qcodes_loop
• Use ParameterWithSetpoints
• Return fast sweep data as array instead of qcodes dataset

[codecov]

Codecov Report

❌ Patch coverage is 75.00000% with 13 lines in your changes missing coverage. Please review.
✅ Project coverage is 60.02%. Comparing base (e386a23) to head (893c7bd).

Files with missing lines	Patch %	Lines
...odes/instrument_drivers/Keithley/_Keithley_2600.py	75.00%	13 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #7851      +/-   ##
==========================================
+ Coverage   59.87%   60.02%   +0.14%     
==========================================
  Files         352      352              
  Lines       31872    31876       +4     
==========================================
+ Hits        19083    19132      +49     
+ Misses      12789    12744      -45     

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