Magit (transient) not reading values file when location is custom

### What did you expect to happen?

I update my transient variables:

```
(setq transient-values-file "~/.doom.d/.transient/values"
transient-history-file "~/.doom.d/.transient/history"
transient-levels-file "~/.doom.d/.transient/levels"))
```

Now the saved transient preferences in magit are saved and loaded from these files.

### What actually happened?

This works for _writing_. Saving preferences in magit (with C-x C-s) saves values to this location (in the values file). However after restarting emacs the values are not read in magit. Note: the variables are still successfully set to this custom location, the file is simply not being used.

### Describe your attempts to resolve the issue

Tried setting these variables at different times, was unable to find a setup that worked.

### Steps to reproduce

1. Set the variables to point to a different custom location
1. Save some new preferences
1. Quite and restart emacs
1. Observe if the preferences are taking effect in magit

### System Information

Latest pull from github