welcome page: remove background in active window when plugin is disabled

Before the change in the plugin enabling would only be effective on
next program start.
1 job for !99 with removewelcomepageondisabling in 60 minutes (queued for 12 minutes and 33 seconds)
detached
Status Job ID Name Coverage
  Build
failed #30647
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
==25285==ABORTING

Start 101: test_cmakeserver
kf5.kinit.klauncher: new app ":1.63"
kf5.kinit.klauncher: new app "org.kdevelop.kdevplatform-lock-63752a30-b412-4c45-874c-0a27058c39cf"
qt.qpa.events: Event | XCB_CLIENT_MESSAGE(33) | sequence: 400
qt.qpa.events: Event | XCB_CLIENT_MESSAGE(33) | sequence: 400
Pulling docker image gitlab/gitlab-runner-helper:x86_64-ac8e767a ...
ERROR: Job failed: execution took longer than 1h0m0s seconds