BranchColor value on config behaves not consistant

**Describe the bug**
Adjusting the branch colors on the UI needs to take RGB values while some other places can take RGB values or named colors like 'blue'. A consistent behavior that allows both (color and RGB) would be nice.

**To Reproduce**
Steps to reproduce the behavior:
1. Open the config file
2. Edit the branch coloring settings (ui:branchColors:)
3. Put down a color name instead RGB like red or 'red' (both tested)
4. Open LazyGit and see that all matching branches are shown black colored (fallback)

**Expected behavior**
Branches that match the pattern should be colored correctly..

**Screenshots**
See that names are black no matter which red/'red' i noted down.For main the RGB code works.

**Desktop (please complete the following information):**
- OS: Manjaro
- Lazygit Version 0.34 (latest - 13.6.2022)