[4.0.rc5] Converter deletes lines that use OS.window_size

[Koopa1018]

Godot version

4.0.rc5.official

System information

Windows 10

Issue description

When converting a project from 3.5.1, the converter completely removes lines that use OS.window_size instead of upgrading them to a Godot 4 equivalent. Quite often this leads to errors, e.g. missing variable declarations, indented blocks with no opening if statement, etc.

Steps to reproduce

1. Open the repro project in Godot 3.5.1 or earlier
2. Inspect contents of demo_script.gd
3. Close Godot 3.5.1 and run a full conversion to Godot 4
4. Open project in Godot 4
5. Observe that demo_script.gd is now in an error state due to lacking a variable declaration

Minimal reproduction project

OS Window Function Error.zip