How to reproduce:
1. Open the attached "controlscheme_playmode_issue" project
2. From the Assets folder, open the “test” Input Action asset
3. Select the “All Control Schemes” dropdown menu and select the “testscheme”
4. Enter and exit Play Mode
5. Select the dropdown menu from step 3 (it should now say “testscheme”) and select “Edit Control Scheme…”

Expected result: “testscheme” is opened for editing
Actual result: An empty window for adding a new scheme is opened, and attempting to save the scheme leads to exceptions being thrown

Reproducible in: 1.8.0-pre.2(2022.3.18f1, 2023.2.7f1, 2023.3.0b4)
Not reproducible in: 1.8.0-pre.1(2021.3.34f1, 2022.3.18f1, 2023.2.7f1), 1.8.0-pre.2 (2021.3.34f1)

Reproducible on: Windows 11, macOS 13.6.3 (Intel)
Not reproducible on: No other environments tested

Note: After entering and exiting Play Mode, the Actions tab in the Input Actions Editor shows bindings for all Control Schemes, even if only a single Control Scheme is selected