ENABLE_MONO and ENABLE_IL2CPP directives are incorrectly defined when entering Play mode

Reproduction steps:
1. Open project “Test_IL2CPP_Conditional_Compilation.zip”
2. Open “SampleScene”
3. Make sure the IL2CPP scripting backend is set in the Project Settings
4. Enter Play mode

Expected result: The editor exits play mode and prints a "IL2CPP scripting backend is enabled." log message in the Console
Actual result: The editor exits play mode and prints a "Mono scripting backend is enabled." log message in the Console

Reproducible with: 2021.3.30f1, 2022.3.9f1, 2023.1.13f1, 2023.2.0b9, 2023.3.0a5

Reproducible on: macOS Ventura 13.2.1 (Intel)
Not reproducible on: no other environment tested

Notes:

• Not reproducible in Standalone Player
• ENABLE_MONO directive is always defined whereas ENABLE_IL2CPP is never defined, regardless of whether the scripting backend is set to Mono or IL2CPP