Fix response body logging under debugger

[Rimobul]

Fixes #7649

Treat only TimeSpan.Zero as an immediate test timeout. This preserves the infinite timeout used while debugging, allowing the response body to be logged without leaving the content stream consumed.

Add regression coverage for seekable and non-seekable streams, with and without response content buffering.

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[Rimobul]

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[Rimobul]

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[Copilot]

Pull request overview

Fixes a regression in Microsoft.Extensions.Http.Diagnostics where response body logging could cancel immediately when a debugger is attached (because Timeout.InfiniteTimeSpan is negative), which could lead to the response content stream being left in an unreadable/consumed state for callers.

Changes:

• Update the response-body read-timeout logic to treat only TimeSpan.Zero as the “cancel immediately” test-only timeout, preserving Timeout.InfiniteTimeSpan behavior under debugger attachment.
• Add regression coverage ensuring response content remains readable after logging for both seekable and non-seekable streams, and with/without LoadIntoBufferAsync (mimicking HttpCompletionOption.ResponseContentRead).

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
test/Libraries/Microsoft.Extensions.Http.Diagnostics.Tests/Logging/HttpResponseBodyReaderTest.cs	Adds combinatorial regression test validating body logging under debugger doesn’t consume/break the response stream (seekable/non-seekable, buffered/unbuffered).
src/Libraries/Microsoft.Extensions.Http.Diagnostics/Logging/Internal/HttpResponseBodyReader.cs	Fixes timeout comparison so Timeout.InfiniteTimeSpan under debugger no longer triggers immediate cancellation.