fix pay_as_clear and pay_as_bid in edge cases

[maurerle]

some bids did appear twice in the rejected bids
bids with an accepted_volume of 0 were still accepted in pay_as_bid

This does produce the expected results for all 4 possible clearing scenarios

Screenshots:

[codecov]

Codecov Report

Attention: Patch coverage is 85.71429% with 2 lines in your changes missing coverage. Please review.

Project coverage is 76.76%. Comparing base (6f628ab) to head (97c1171).

Files with missing lines	Patch %	Lines
assume/markets/clearing_algorithms/simple.py	85.71%	2 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #466   +/-   ##
=======================================
  Coverage   76.75%   76.76%           
=======================================
  Files          50       50           
  Lines        6272     6278    +6     
=======================================
+ Hits         4814     4819    +5     
- Misses       1458     1459    +1     

Flag	Coverage Δ
pytest	76.76% <85.71%> (+<0.01%)	⬆️

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