Move the file back to the original location.
Then - inside PP - choose „Save As…“ to store it in the new location.
Move it back to the original location.
In the „settings“ choose „store settings next to file“
Move both files to the new solution
The workspace directory contains a cryptic file name with the configuration. The name is hashed out of the location of the file. If you cannot move the file back to the old location, let me know if you want to identify this route.
Maybe one word why this is the way it is: the idea is that all local settings are just stored locally. It should only include things that do not make sense when moving to a new computer. For example, the width of some UI elements, the width of columns in pixel, etc. Unfortunately, not all information is cleanly separated.
Maybe I should make the „store settings next to portfolio file“ the default option.