Ensure all XRay Sampler functionality is under ParentBased logic

[jj22ee]

This fixes the bug where:

• Currently, XRay Sampler in OTel Go will use ShouldSample logic for every span, but for child spans, they should always respect the parent span sampling decision in XRay Sampler (as is already done in OTel Java and OTel .NET)

The changes introduced in this PR are as follows:

• Wrap the returned remote_sampler of NewRemoteSampler under a single ParentBased Sampler

Existing Issue(s):
Related

• [XRay Sampler] - XRay Sampler Statistics reports much higher RequestCount/SampleCount than expected for Sampling Rules  aws-observability/aws-otel-js-instrumentation#79
• [XRay Sampler] Fix - Ensure all XRay Sampler functionality is under ParentBased logic aws-observability/aws-otel-js-instrumentation#80

Testing:

• Tested Sampler functionality with XRay Sampler test bed - https://github.com/aws-observability/aws-otel-community/tree/master/centralized-sampling-tests

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 67.7%. Comparing base (64a1336) to head (80f4bb0).
Report is 10 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##            main   #6205     +/-   ##
=======================================
+ Coverage   67.4%   67.7%   +0.2%     
=======================================
  Files        206     206             
  Lines      13220   13220             
=======================================
+ Hits        8922    8958     +36     
+ Misses      3996    3957     -39     
- Partials     302     305      +3     

Files with missing lines	Coverage Δ
samplers/aws/xray/remote_sampler.go	37.3% <100.0%> (+34.3%)	⬆️

... and 3 files with indirect coverage changes

[dmathieu]

👎
Ensuring this is the responsibility of the developer using this sampler in their own application.
This change prevents folks from setting up their own parent-based logic and using that.

[MrAlias]

Thank you for your interest in the project. We have recently removed this sampler (#6187) as it does not have an owner. I'm closing this as we are no longer accepting changes to this code.