"PlayerPrefs.GetString" returns an empty string when the default value is set to "null"

Reproduction steps:
1. Open project “PlayerPrefsRepro.zip”
2. Open “SampleScene”
3. Enter Play Mode
4. Observe the Console

Expected result: No error is thrown
Actual result: “AssertionException: Assertion failure. Values are not equal. Expected: == “ error is thrown in the console

Reproducible with: 2021.3.30f1, 2022.3.9f1, 2023.1.12f1, 2023.2.0b8, 2023.3.0a4

Reproducible on: macOS Ventura 13.2.1 (Intel), Windows 11 (by the reporter)
Not reproducible on: no other environment tested

Notes:

• Also reproducible in Standalone Player
• changing line 12 in “Repro.cs” to Assert.AreEqual("", PlayerPrefs.GetString("test-key", null)); gives Expected results