In editor, progress bar gets stuck if auto mode toggle button is disabled while building the lighting, as if it still continues to build the lighting. UI bar needs to be repainted when auto mode is disabled.

Steps for reproduction:
1) Create a new project or open the project attached below
2) Ensure that auto mode is on and build the lighting
3) While the lighting is building, disable the auto mode
4) Observe the bug. Progress bar is stuck

Notes:
- Ensured that it’s a UI issue, checking the editor.log in Baretail proves that everything works as expected
- Regression introduced in 5.6.0b3, it is reproducible onward
- Not reproducible in 5.6.0b2 and older versions
- Same issue also occurs when lighting process is cancelled after pressing on `Generate Lighting` button