Draw qubit reset and postselection with matplotlib

[albi3ro]

This PR accomplishes two main things:

• Indicates postselection on the icon for mid circuit measurements
• Indicates reset with erasing the wire line and restarting it after a |0> box.

There is a regression in the handling of conditionals, as drawing conditionals will be standardized in a follow-up PR.

While doing so, I also:

• converted from a hacky single dispatch to functools.singledispatch to register custom ways to display operations
• Moved Conditional to the ops.op_math submodule to avoid a circular dependency. This can be accomplished in a separate PR instead.

[sc-50118]

[trbromley]

Thanks @albi3ro, this looks great! One minor suggestion, which could be done in a separate PR: could the measurement symbol (semicircle and arrow) be moved downwards inside the box so that it is centre-aligned vertically?

[albi3ro]

@trbromley like this?

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (8d1a94e) 99.65% compared to head (7cf7027) 99.64%.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #4832      +/-   ##
==========================================
- Coverage   99.65%   99.64%   -0.02%     
==========================================
  Files         383      383              
  Lines       34582    34341     -241     
==========================================
- Hits        34462    34218     -244     
- Misses        120      123       +3     

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

[mudit2812]

Looks great Christina!

Is it possible to lower the number drawn for postselection? Imo it's too close to the measurement symbol. Other than than, I'm ready to approve.

[mudit2812]

The link to this PR still needs to be added to the changelog, but other than that looks good! Thanks Christina, the singledispatch was a really good change as well

[timmysilv]

what is the plan for conditionals? are we going to restore them to the current behaviour, or do something all-new? not entirely sure why it should be done in another PR, but i'm fine to keep things separated with a plan laid out

[albi3ro]

what is the plan for conditionals? are we going to restore them to the current behaviour, or do something all-new? not entirely sure why it should be done in another PR, but i'm fine to keep things separated with a plan laid out

@timmysilv PR #4850 . Depends on Mudit's PR #4803 .

[timmysilv]

looks good!