[sampling] Inherit default per-operation strategies

[yurishkuro]

Which problem is this PR solving?

• Part 2 of [Bug]: Operation based sampling strategies are not being returned for ratelimiting service strategies #5270

Description of the changes

• 🛑 Make the new behavior to inherit from default strategy to be ON by default.
• In v1 it can still be disabled via a flag, which will be deprecated in the future.
• In v2 it can be disabled via a feature gate jaeger.sampling.includeDefaultOpStrategies

How was this change tested?

• CI

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 96.27%. Comparing base (752e8d2) to head (ab896dc).
Report is 6 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #6441   +/-   ##
=======================================
  Coverage   96.26%   96.27%           
=======================================
  Files         369      369           
  Lines       21051    21052    +1     
=======================================
+ Hits        20265    20268    +3     
+ Misses        602      600    -2     
  Partials      184      184           

Flag	Coverage Δ
badger_v1	10.53% <ø> (ø)
badger_v2	2.59% <ø> (ø)
cassandra-4.x-v1-manual	16.41% <ø> (ø)
cassandra-4.x-v2-auto	2.52% <ø> (ø)
cassandra-4.x-v2-manual	2.52% <ø> (ø)
cassandra-5.x-v1-manual	16.41% <ø> (ø)
cassandra-5.x-v2-auto	2.52% <ø> (ø)
cassandra-5.x-v2-manual	2.52% <ø> (ø)
elasticsearch-6.x-v1	20.14% <ø> (ø)
elasticsearch-7.x-v1	20.22% <ø> (ø)
elasticsearch-8.x-v1	20.38% <ø> (ø)
elasticsearch-8.x-v2	2.58% <ø> (ø)
grpc_v1	12.19% <ø> (ø)
grpc_v2	8.97% <ø> (ø)
kafka-3.x-v1	10.37% <ø> (ø)
kafka-3.x-v2	2.59% <ø> (ø)
memory_v2	2.58% <ø> (-0.01%)	⬇️
opensearch-1.x-v1	20.26% <ø> (ø)
opensearch-2.x-v1	20.26% <ø> (ø)
opensearch-2.x-v2	2.59% <ø> (ø)
tailsampling-processor	0.39% <ø> (ø)
unittests	95.14% <100.00%> (+<0.01%)	⬆️

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