[MRG] Adding picklist arg to sourmash_args.load_picklist to allow the option

[ccbaumler]

Fixes #3838

This PR allows for the entire namespace to be used with the sourmash_args.load_picklist function as well as a correctly formatted picklist string.
i.e

        picklist_arg = f"{pickfile}:{colname}:{coltype}:{pickstyle.name.lower()}"

This will be used in conjunction with #3837 in pangenomics scripts

Ref:
https://stackoverflow.com/questions/34869889/what-is-the-proper-way-to-determine-if-an-object-is-a-bytes-like-object-in-pytho
https://realpython.com/ref/builtin-functions/isinstance/

[codecov]

Codecov Report

❌ Patch coverage is 9.09091% with 10 lines in your changes missing coverage. Please review.
✅ Project coverage is 48.12%. Comparing base (d2096c0) to head (ecdbc56).

Files with missing lines	Patch %	Lines
src/sourmash/sourmash_args.py	9.09%	10 Missing ⚠️

❗ There is a different number of reports uploaded between BASE (d2096c0) and HEAD (ecdbc56). Click for more details.

HEAD has 36 uploads less than BASE

Flag	BASE (d2096c0)	HEAD (ecdbc56)
python	28	0
hypothesis-py	5	1
rust	5	1

Additional details and impacted files

@@             Coverage Diff             @@
##           latest    #3839       +/-   ##
===========================================
- Coverage   88.15%   48.12%   -40.04%     
===========================================
  Files         137      137               
  Lines       22610    22614        +4     
  Branches     2303     2305        +2     
===========================================
- Hits        19931    10882     -9049     
- Misses       2366    11532     +9166     
+ Partials      313      200      -113     

Flag	Coverage Δ
hypothesis-py	25.22% <9.09%> (-0.01%)	⬇️
python	?
rust	81.63% <ø> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.

[ccbaumler]

This update was necessary to build the tests here sourmash-bio/sourmash_utils#8

And for sourmash plugin support.