Foreground color (dark blue) for git commit graph is hard to read

### Describe the bug
The default color (dark blue) used for the git graph is hard to read on the dark terminal background.

### To Reproduce
Steps to reproduce the behavior:

1. Default installation, enable "Show whole git graph"
2. Notice the dark blue graph indicators

### Expected behavior
The foreground color is easily read against the background color.

### Screenshots

### Version info:

* commit=, build date=, build source=Homebrew, version=0.61.1, os=darwin, arch=arm64, git version=2.54.0

### Terminal info:
Ghostty, had this issue with the default theme as well as "Dracula", and likely more.

### Additional context

Unlike most of the other UI which uses lighter colors from the palette, the dark blue is too hard to make out.