invoke lambda feature work: AWS Account ID Parsing

[tippmar-nr]

• Adds AWS account ID parsing logic plus unit tests. Includes profiler update.
• Tweaks to ArnBuilder to default to non-empty strings, tests updated as necessary
• Miscellaneous refactoring in ContainerIntegrationTests project

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 81.47%. Comparing base (c36d25c) to head (75a6696).

Additional details and impacted files

@@                            Coverage Diff                            @@
##           feature/invoke-lambda-instrumentation    #2911      +/-   ##
=========================================================================
+ Coverage                                  81.44%   81.47%   +0.02%     
=========================================================================
  Files                                        466      467       +1     
  Lines                                      29692    29723      +31     
  Branches                                    3305     3309       +4     
=========================================================================
+ Hits                                       24182    24216      +34     
+ Misses                                      4715     4713       -2     
+ Partials                                     795      794       -1     

Flag	Coverage Δ
Agent	82.39% <100.00%> (+0.03%)	⬆️
Profiler	73.13% <ø> (ø)

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Files with missing lines	Coverage Δ
...ons/NewRelic.Agent.Extensions/AwsSdk/ArnBuilder.cs	96.87% <100.00%> (-3.13%)	⬇️
...lic.Agent.Extensions/AwsSdk/AwsAccountIdDecoder.cs	100.00% <100.00%> (ø)

... and 2 files with indirect coverage changes