fix: When sql explain plan generation fails, don't attempt to generate an explain plan on future invocations of the same query.

[tippmar-nr]

Adds a cache for tracking queries where explain plan generation attempt throws an exception, so that future execution of the same query will not attempt to generate an explain plan. This fix will help ensure database performance doesn't suffer due to repeated, failed explain plan generation attempts.

Cache capacity is configured to 1000 queries, which should be far more than we ever experience in the wild - it is anticipated that explain plan failures are a very rare occurrence.

Includes unit and integration tests.

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 97.36842% with 1 line in your changes missing coverage. Please review.

Project coverage is 82.29%. Comparing base (121c6b8) to head (fab571a).
Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
...wRelic/Agent/Core/Segments/DatastoreSegmentData.cs	95.23%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3075      +/-   ##
==========================================
+ Coverage   82.22%   82.29%   +0.07%     
==========================================
  Files         477      477              
  Lines       30627    30659      +32     
  Branches     3426     3429       +3     
==========================================
+ Hits        25182    25232      +50     
+ Misses       4644     4627      -17     
+ Partials      801      800       -1     

Flag	Coverage Δ
Agent	83.36% <97.36%> (+0.08%)	⬆️
Profiler	72.51% <ø> (ø)

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

Files with missing lines	Coverage Δ
...elic/Agent/Core/Database/CacheByDatastoreVendor.cs	100.00% <100.00%> (ø)
...s/NewRelic.Agent.Extensions/Caching/SimpleCache.cs	98.50% <100.00%> (+11.20%)	⬆️
...wRelic/Agent/Core/Segments/DatastoreSegmentData.cs	92.81% <95.23%> (+10.69%)	⬆️

... and 4 files with indirect coverage changes

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.