fix: Remove remaining default configuration.

[tank-500m]

Description

Removed the remaining default configuration.
OTLP exporter’s default load balancing is intended to be round_robin.

Link to tracking issue

Fixes #
#14090

Testing

Documentation

[dmitryax]

Please document this change better with all side effects and add a changelog item

[codspeed-hq]

Merging this PR will degrade performance by 30.21%

⚠️ Unknown Walltime execution environment detected

Using the Walltime instrument on standard Hosted Runners will lead to inconsistent data.

For the most accurate results, we recommend using CodSpeed Macro Runners: bare-metal machines fine-tuned for performance measurement consistency.

Summary

❌ 4 regressed benchmarks
✅ 55 untouched benchmarks
⏩ 20 skipped benchmarks¹

⚠️ Please fix the performance issues or acknowledge them on CodSpeed.

Performance Changes

	Benchmark	BASE	HEAD	Efficiency
❌	BenchmarkLogsToProto2k	44.7 µs	63.1 µs	-29.21%
❌	BenchmarkProfilesToProto	1.2 µs	1.7 µs	-27.05%
❌	BenchmarkTraceSizeBytes	299.8 µs	429.5 µs	-30.21%
❌	BenchmarkTracesToProto2k	69.9 µs	96.6 µs	-27.6%

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_{Comparing tank-500m:fix-otlp-default-balancer (b9bd07d) with main (ee8646e)}

Footnotes

1. 20 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩