UI Builder background color picker alpha values are set to even numbers when saving alpha value as an odd number

Steps to reproduce:
1. Create a new project
2. Create a UI Document (Right Click → Create → UI Toolkit → UI Document)
3. Open the UI Document
4. Add a VisualElement
5. Select the VisualElement
6. Navigate to background section in the UI Builder Inspector
7. Open the color picker
8. Change the alpha value to any odd number that is not 255
9. Exit the color picker and save the UI Document
10. Open the color picker
11. Observe the color picker values

Expected Result: Alpha value stays the same
Actual result: Alpha value is turned to an even number

Reproducible with: 2023.1.0a1, 6000.0.62f1, 6000.2.12f1, 6000.3.0b10, 6000.4.0a4, 6000.5.0a1

Reproducible on: Windows 11 Pro (24H2)
Not reproducible on: No other environments tested