Update `TraceIdRatioBasedSampler` to calculate sampling threshold according to OTEP 235

[Nevay]

Computes the sampling threshold as defined in https://github.com/open-telemetry/opentelemetry-specification/pull/4166.

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 68.85%. Comparing base (20bf3cf) to head (96bebeb). Report is 73 commits behind head on main.

Additional details and impacted files

@@             Coverage Diff              @@
##               main    #1391      +/-   ##
============================================
- Coverage     73.56%   68.85%   -4.72%     
- Complexity     2672     3181     +509     
============================================
  Files           386      415      +29     
  Lines          7650     9285    +1635     
============================================
+ Hits           5628     6393     +765     
- Misses         2022     2892     +870     

Flag	Coverage Δ
8.1	70.51% <100.00%> (?)
8.2	70.73% <100.00%> (?)
8.3	70.73% <100.00%> (?)
8.4	68.82% <100.00%> (-4.75%)	:arrow_down:

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Files with missing lines	Coverage Δ
src/SDK/Trace/Sampler/TraceIdRatioBasedSampler.php	100.00% <100.00%> (ø)

... and 274 files with indirect coverage changes

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[stale[bot]]

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