Slick 3.5.0 bug fix

[kanderson250]

Resolves #1996

Previously, our slick instrumentation wrapped the slick AsyncExecutor in our own NewRelicAsyncExecutor. However, in slick 3.5.0, the concrete implementation AsyncExecutorImpl was introduced, which meant our wrapper ignored AsynExecutorImpl's overridden methods. One consequence of that was incorrect creation of PrioritizedRunnables and disruption of the executor's work queue, causing the application to stall.

We also recognized that wrapping slick's PrioritizedRunnable in a Runnable (only for slick to wrap it back into a PrioritizedRunnable) was less than ideal.

This instrumentation avoids wrapping anything so that we don't have the type issues from before. Instead, we now instrument the prioritizedRunnable method on AsyncExecutor and wrap its generic run Function parameter.

Thanks to @jmreardon-yoppworks for filing the initial bug report and providing a repro to aid our development work.

** Tests **
There are a few new unit tests, plus an AIT branch that has been updated with the new slick module.

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 70.58%. Comparing base (9338ecc) to head (a439eb9).
Report is 31 commits behind head on main.

Additional details and impacted files

@@             Coverage Diff              @@
##               main    #2025      +/-   ##
============================================
- Coverage     70.60%   70.58%   -0.02%     
- Complexity     9872     9875       +3     
============================================
  Files           829      829              
  Lines         39914    39945      +31     
  Branches       6077     6078       +1     
============================================
+ Hits          28181    28195      +14     
- Misses         9002     9020      +18     
+ Partials       2731     2730       -1     

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