plugins: hide tileseditor and windowview effects from KCM

Part of https://invent.kde.org/plasma/systemsettings/-/issues/39

These don't make much sense to disable as they're completely benign when
not in use. Their config windows only contain shortcuts which are already
in the Shortcuts KCM, so they're harmless to hide from the Desktop
Effects KCM.

src/plugins/tileseditor/metadata.json

@@ -86,5 +86,8 @@
         "Name[zh_CN]": "磁贴编辑器",
         "Name[zh_TW]": "平鋪方塊編輯器"
     },
-    "X-KDE-ConfigModule": "kwin_tileseditor_config"
+    "X-KDE-ConfigModule": "kwin_tileseditor_config",
+    "org.kde.kwin.effect": {
+        "internal": true
+    }
 }

src/plugins/windowview/metadata.json

@@ -97,5 +97,8 @@
         "Name[zh_CN]": "窗口平铺展示",
         "Name[zh_TW]": "展示視窗"
     },
-    "X-KDE-ConfigModule": "kwin_windowview_config"
+    "X-KDE-ConfigModule": "kwin_windowview_config",
+    "org.kde.kwin.effect": {
+        "internal": true
+    }
 }