[tests] RecordTest.DeskCase_83099_InmutableDictionary is flaky on macOS CI

[rolfbjarne]

The test MonoTouchFixtures.Security.RecordTest.DeskCase_83099_InmutableDictionary is flaky on macOS CI machines.

Failure

The test fails intermittently with:

Password could not be saved to keychain. queryCode: ItemNotFound addCode: DuplicateItem updateCode: -1
Expected: True
But was: False

The keychain reports DuplicateItem when adding, but ItemNotFound when querying — indicating inconsistent keychain state on the CI machine.

Recent occurrence

• PR [dotnet-linker] Export DOTNET for csproj.inc generation. #24852, build 13498339, monotouch-test/macOS/Debug
• Execution log

Possible fixes

• Clean up the keychain entry before/after the test to avoid stale state from previous runs.
• Repeat the test a few times to see if it eventually passes