This reverts upstream commit bc67535891d6bfba5c8fce71acaec70c02d6df50.

This appears to need some version of ECM that is not released / KF6 only.
Which doesn't make sense, because KF5WebKit is removed in KF6!

See-also: https://invent.kde.org/frameworks/kdewebkit/-/commit/bc67535891d6bfba5c8fce71acaec70c02d6df50

--- kdewebkit-5.116.0/CMakeLists.txt.old	2024-05-04 06:39:11.000000000 -0500
+++ kdewebkit-5.116.0/CMakeLists.txt	2025-07-01 03:57:32.618642093 -0500
@@ -76,5 +76,4 @@
   DESTINATION ${KDE_INSTALL_INCLUDEDIR_KF5}/KDEWebKit COMPONENT Devel
 )
 
-include(ECMFeatureSummary)
-ecm_feature_summary(WHAT ALL   FATAL_ON_MISSING_REQUIRED_PACKAGES)
+feature_summary(WHAT ALL   FATAL_ON_MISSING_REQUIRED_PACKAGES)