chore(deps): update opentelemetry-dotnet monorepo to 1.15.3

[renovate]

This PR contains the following updates:

Package	Change	Age	Confidence
OpenTelemetry (source)	1.15.2 → 1.15.3
OpenTelemetry.Exporter.InMemory (source)	1.15.2 → 1.15.3
OpenTelemetry.Extensions.Hosting (source)	1.15.2 → 1.15.3

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Release Notes

open-telemetry/opentelemetry-dotnet (OpenTelemetry)

v1.15.3

Release details: 1.15.3

• Breaking change: Fixed tracestate parsing to reject keys that do not
  begin with a lowercase letter, including keys beginning with digits, to
  align with the W3C Trace Context specification.
• Breaking change: Fixed an insecure disk retry default for OTLP export.
  Disk retry now requires OTEL_DOTNET_EXPERIMENTAL_OTLP_DISK_RETRY_DIRECTORY_PATH
  when OTEL_DOTNET_EXPERIMENTAL_OTLP_RETRY=disk is configured.
• Improve efficiency of parsing of baggage and B3 propagation headers.
• OtlpLogExporter now uses IHttpClientFactory on .NET 8+.
• Fixed an issue in OTLP/gRPC retry handling when parsing gRPC statuses.
• Fixed OTEL_SPAN_ATTRIBUTE_VALUE_LENGTH_LIMIT not being applied.
• Fixed baggage and trace headers not respecting the maximum length in some cases.
• Fixed BaggagePropagator to trim optional whitespace (OWS) around =
  separators when parsing the baggage header.
• Fixed BaggagePropagator to strip baggage properties from values when
  parsing the baggage header.
• Fixed OTLP persistent storage clean-up handling for malformed filenames.
• Fixed resource leak in batch and periodic exporting task workers for Blazor/WASM.
• Fixed LogRecord.LogLevel to preserve LogLevel.None.
• Fixed OTEL_TRACES_SAMPLER_ARG handling for out-of-range values.
• Fixed an issue with OTLP disk retry storage where metrics and logs used the
  traces storage directory.
• Fixed full OTLP endpoint being logged by internal diagnostics.
• Improve efficiency of parsing of baggage, B3 and Jaeger propagation headers.
• Hardened Zipkin exporter memory usage for endpoint caching and array tag
  serialization.

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 93.47%. Comparing base (ec94acf) to head (32b43cf).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #751   +/-   ##
=======================================
  Coverage   93.47%   93.47%           
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  Files          68       68           
  Lines        2956     2956           
  Branches      351      351           
=======================================
  Hits         2763     2763           
  Misses        135      135           
  Partials       58       58           

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