Splashscreens don't replace properly

[Eeems]

Describe the issue Splashscreens are setup to replace the same metapackage so that when you install one, it'll replace the other one of the same type. Instead it'll error about them providing the same file.

To Reproduce Steps to reproduce the behaviour:

1. Install a splashscreen package
2. Attempt to install another splashscreen package of the same type
3. Get an error about both packages providing the same file

Expected behaviour The package installation will work, and the previous package will be removed, or it will provide a meaningful error about not being able to install as the other package is already installed.

Upstream issue N/A

Screenshots N/A

Additional context #724