Prevent infinite loop in gRPC tracing during span storage.

[ldlb9527]

fixes: #5971

I'm not sure if this is reasonable, so please let me know if there are any issues.

[codecov]

Codecov Report

Attention: Patch coverage is 86.36364% with 3 lines in your changes missing coverage. Please review.

Project coverage is 51.46%. Comparing base (7787010) to head (5ae15ad).
Report is 12 commits behind head on main.

Files with missing lines	Patch %	Lines
plugin/storage/grpc/factory.go	78.57%	2 Missing and 1 partial ⚠️

❗ There is a different number of reports uploaded between BASE (7787010) and HEAD (5ae15ad). Click for more details.

HEAD has 1 upload less than BASE

Flag	BASE (7787010)	HEAD (5ae15ad)
unittests	1	0

Additional details and impacted files

@@             Coverage Diff             @@
##             main    #5979       +/-   ##
===========================================
- Coverage   96.82%   51.46%   -45.36%     
===========================================
  Files         345      176      -169     
  Lines       16523     8876     -7647     
===========================================
- Hits        15998     4568    -11430     
- Misses        339     3864     +3525     
- Partials      186      444      +258     

Flag	Coverage Δ
badger_v1	8.02% <0.00%> (-0.01%)	⬇️
badger_v2	1.82% <0.00%> (-0.01%)	⬇️
cassandra-4.x-v1	16.60% <0.00%> (-0.01%)	⬇️
cassandra-4.x-v2	1.75% <0.00%> (-0.01%)	⬇️
cassandra-5.x-v1	16.60% <0.00%> (-0.01%)	⬇️
cassandra-5.x-v2	1.75% <0.00%> (-0.01%)	⬇️
elasticsearch-6.x-v1	18.76% <0.00%> (-0.03%)	⬇️
elasticsearch-7.x-v1	18.83% <0.00%> (+<0.01%)	⬆️
elasticsearch-8.x-v1	19.02% <0.00%> (-0.03%)	⬇️
elasticsearch-8.x-v2	1.81% <0.00%> (-0.02%)	⬇️
grpc_v1	9.54% <86.36%> (+0.03%)	⬆️
grpc_v2	7.15% <0.00%> (+<0.01%)	⬆️
kafka-v1	9.73% <0.00%> (-0.01%)	⬇️
kafka-v2	1.82% <0.00%> (-0.01%)	⬇️
memory_v2	1.81% <0.00%> (-0.02%)	⬇️
opensearch-1.x-v1	18.88% <0.00%> (+<0.01%)	⬆️
opensearch-2.x-v1	18.88% <0.00%> (-0.01%)	⬇️
opensearch-2.x-v2	1.82% <0.00%> (+0.01%)	⬆️
tailsampling-processor	0.46% <0.00%> (-0.01%)	⬇️
unittests	?

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