Installer: 256MG boot partition created when choosing to use an entire partition

Please confirm there isn't an open report for this issue

• I have searched through bug reports

Summary

Recently, I installed Solus on a new laptop using the 4.8 Plasma ISO. I chose to use a specific partition on the disk since it's a dual-boot machine. During one install I saw errors from clr-boot-mananger that /boot was out of space. It only had 256MB available

Steps to reproduce

1. When installing Solus choose to use a specific partition and let Solus configure its partitions
2. Finish install as normal

Expected result

The /boot partition is 1GiB per requirements

Actual result

The /boot partition is only 256MB

Environment

• Is system up to date?

Repo

Unstable

Desktop Environment

Plasma

System details

 ~/k/src > df -h | rg "File|nv"                    
Filesystem      Size  Used Avail Use% Mounted on
/dev/nvme0n1p5  192G   50G  133G  28% /
/dev/nvme0n1p6  600G   89G  480G  16% /home
/dev/nvme0n1p1  256M  228M   29M  90% /boot

 ~/k/src > kinfo        
Operating System: Solus 4.8
KDE Plasma Version: 6.5.3
KDE Frameworks Version: 6.12.0
Qt Version: 6.10.1
Kernel Version: 6.17.8-324.current (64-bit)
Graphics Platform: Wayland
Processors: 8 × Intel® Core™ Ultra 7 258V
Memory: 32 GiB of RAM (30.9 GiB usable)
Graphics Processor: Intel® Graphics

Other comments

@silkeh - This should be added to the automated installer tests - to check that /boot is at least 1GiB after any type of installation

Reproduce the specific-partition installation described in the issue, then trace the installer’s partition-configuration entry point. Add or update the automated installer tests mentioned in the report, and verify that installations of each supported type create a /boot partition of at least 1 GiB.