Remove unused KConfigXT usage

This was cautgh by my kconfig_compiler rework, it broke generating
the files for KDevelop, but the reason was that there was no
configurations at all in the kcfg file, and was also never used in
this specific class was never used in kdevelop.
1 job for !90 with remove_unused_code in 60 minutes (queued for 21 minutes and 9 seconds)
latest detached
Status Job ID Name Coverage
  Build
failed #28927
linux kf5-qt5 qt5.12

01:00:00

 
Name Stage Failure
failed
linux kf5-qt5 qt5.12 Build The script exceeded the maximum execution time set for the job
 85/123 Test  #85: test_qmljscontexts ......................   Passed   11.87 sec
Start 86: test_qmljsdeclarations
kf5.kinit.klauncher: new app ":1.49"
kf5.kinit.klauncher: new app "org.kdevelop.kdevplatform-lock-5d07a256-e0ff-4e3c-8fd6-ceb7e0ad42ca"
86/123 Test #86: test_qmljsdeclarations .................. Passed 6.46 sec
Start 87: test_files
kf5.kinit.klauncher: new app ":1.50"
Pulling docker image gitlab/gitlab-runner-helper:x86_64-ac8e767a ...
ERROR: Job failed: execution took longer than 1h0m0s seconds