feat: add forceflush_timeout configurability

[kovaszab]

Changes

Adds configurability of force flushing timeout for batch processors (BatchSpanProcessor, BatchLogProcessor).

Merge requirement checklist

• CONTRIBUTING guidelines followed
• Unit tests added/updated (if applicable)
• Appropriate CHANGELOG.md files updated for non-trivial, user-facing changes
• Changes in public API reviewed (if applicable)

[linux-foundation-easycla]

The committers listed above are authorized under a signed CLA.

• ✅ login: kovaszab / name: Kovács Szabolcs (2d11e07, 4842c8b, b64f632, c18c006, d5550d6)

[codecov]

Codecov Report

❌ Patch coverage is 49.01961% with 26 lines in your changes missing coverage. Please review.
✅ Project coverage is 80.6%. Comparing base (cff5728) to head (2d11e07).
⚠️ Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
opentelemetry-sdk/src/logs/batch_log_processor.rs	33.3%	4 Missing ⚠️
opentelemetry-sdk/src/logs/logger_provider.rs	55.5%	4 Missing ⚠️
opentelemetry-sdk/src/trace/export.rs	0.0%	4 Missing ⚠️
opentelemetry-sdk/src/trace/span_processor.rs	60.0%	4 Missing ⚠️
opentelemetry-sdk/src/logs/log_processor.rs	60.0%	2 Missing ⚠️
...y-sdk/src/logs/log_processor_with_async_runtime.rs	33.3%	2 Missing ⚠️
opentelemetry-sdk/src/logs/mod.rs	0.0%	2 Missing ⚠️
opentelemetry-proto/src/transform/logs.rs	0.0%	1 Missing ⚠️
...telemetry-sdk/src/logs/concurrent_log_processor.rs	0.0%	1 Missing ⚠️
opentelemetry-sdk/src/trace/mod.rs	0.0%	1 Missing ⚠️
... and 1 more

Additional details and impacted files

@@           Coverage Diff           @@
##            main   #3223     +/-   ##
=======================================
- Coverage   80.8%   80.6%   -0.2%     
=======================================
  Files        128     128             
  Lines      23288   23204     -84     
=======================================
- Hits       18821   18725     -96     
- Misses      4467    4479     +12     

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[cijothomas]

for shutdown, we allow users to pass timeout in each shutdown call itself. Could we stick with the same for flush also?

[cijothomas]

Its best to be consistent with shutdown, if at all we are adding timeout to flush.
i.e Add this all the way from provider itself.

[kovaszab]

You're right, I'll refactor the code to mirror the propagation of the provider's timeout like we do for shutdown_with_timeout.

[cijothomas]

See https://github.com/open-telemetry/opentelemetry-rust/pull/3223/files#r2495071383
Want to see if there is a reason for this be done differently than Shutdown timeouts.