Disable iOS LibraryMode tests by design, drop tracking-issue reference

[Copilot]

The iOS.Device/Simulator.LibraryMode.Test projects were excluded from Apple-mobile runs against a tracking issue that is now being closed. Per reviewer feedback, an exclusion should either be fixed, deleted, or marked "by design" without an ActiveIssue reference.

Changes

• src/libraries/tests.proj: Replaced the <!-- Tracking issue: ... --> comment above the two LibraryMode ProjectExclusions with a by-design comment, matching the convention used by other permanent exclusions in this file (e.g. <!-- PNSE -->).

<!-- Library mode is not supported on Apple mobile; excluded by design. Use RunDisablediOSTests=true to run locally. -->
<ProjectExclusions Include="$(RepoRoot)/src/tests/FunctionalTests/iOS/Device/LibraryMode/iOS.Device.LibraryMode.Test.csproj" />
<ProjectExclusions Include="$(RepoRoot)/src/tests/FunctionalTests/iOS/Simulator/LibraryMode/iOS.Simulator.LibraryMode.Test.csproj" />

Notes

• The exclusion items are unchanged: tests remain off by default for Apple mobile and can still be run locally with RunDisablediOSTests=true.
• This was the only genuine in-repo reference to the issue; the other grep hit (SlhDsaTestData.cs) is a coincidental hex substring in test-vector data.

• Fixes iOS.Device/Simulator.LibraryMode.Test: failed to determine exit code - RETURN_CODE_NOT_SET #116558

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Copilot's findings

• Files reviewed: 1/1 changed files
• Comments generated: 1