Bug 496400

SUMMARY
When using a label longer than 10 characters for an exFAT volume, KPartitionManager fails to apply those changes and the error displayed doesn't provide any information on why it failed.

STEPS TO REPRODUCE
1. Create an exFAT volume
2. Set the value of "Label" to "LongLongLabel"
3. Apply the changes

OBSERVED RESULT
- KPartitionManager fails to apply the changes.
- The "Details" view of the corresponding job displays:

> Job: Set the file system label on partition ‘/dev/sdb1’ to "LongLongLabel" 
> Command: tune.exfat /dev/sdb1 -L LongLongLabel 
> Set the file system label on partition ‘/dev/sdb1’ to "LongLongLabel": Error
> Create a new partition (58,94 GiB, exfat) on ‘/dev/sdb’: Error

EXPECTED RESULT
KPartitionManager doesn't allow to set labels on exFAT longer than 10 characters and shows a corresponding validation failure in at least the following dialogs:
- Right click on volume → Properties
- Right click on unallocated space → New

SOFTWARE/OS VERSIONS
Operating System: NixOS 24.11
KDE Plasma Version: 6.2.3
KDE Frameworks Version: 6.8.0
Qt Version: 6.8.0
Kernel Version: 6.6.60 (64-bit)
Graphics Platform: Wayland
Processors: 4 × Intel® Core™ i5-6200U CPU @ 2.30GHz
Memory: 19.4 GiB of RAM
Graphics Processor: Mesa Intel® HD Graphics 520

ADDITIONAL INFORMATION
When executing "tune.exfat /dev/sdb1 -L LongLongLabel" manually (which is what the job details show, is also executed by KPartitionManager), it displays a helpful message:
> exfatprogs version : 1.2.5
> input string is too long
> failed to encode volume label

So another change that probably should be made is, to display the command output in the "Details" view, since this would have more easily allowed to figure out what actually went wrong.