fix selectbox is not resettable

[kevinpapst]

Description

The system config "Type of select-boxes in forms" could not be resettled after switching to Javascript.
This PR fixes the behavior and introduces the "required" flag for dynamic system configs.

Types of changes

• Bug fix (non-breaking change which fixes an issue)

Checklist

• I verified that my code applies to the guidelines (composer kimai:code-check)
• I agree that this code is used in Kimai and will be published under the MIT license

[codecov]

Codecov Report

Merging #901 into master will increase coverage by <.01%.
The diff coverage is 94.44%.

@@             Coverage Diff             @@
##             master    #901      +/-   ##
===========================================
+ Coverage     94.19%   94.2%   +<.01%     
- Complexity     2582    2586       +4     
===========================================
  Files           277     277              
  Lines          8030    8036       +6     
===========================================
+ Hits           7564    7570       +6     
  Misses          466     466

Impacted Files	Coverage Δ	Complexity Δ
src/Form/Type/EnhancedSelectboxType.php	100% <ø> (ø)	2 <0> (ø)	⬇️
src/Controller/SystemConfigurationController.php	97.82% <100%> (+0.01%)	17 <0> (ø)	⬇️
src/Form/Type/SystemConfigurationType.php	87.5% <100%> (ø)	6 <0> (ø)	⬇️
src/Form/Model/Configuration.php	92.5% <93.33%> (+1.07%)	18 <14> (+4)	⬆️

[lock]

This thread has been automatically locked since there has not been any recent activity after it was closed. Please open a new issue for related bugs. If you use Kimai on a daily basis, please consider donating to support further development of Kimai.