Expose effect ID to scripting via `effect.pluginId`

This can be used to avoid code duplication by installing an effect multiple
times and tweaking behavior slightly based on the returned ID.

Internally it is called `scriptName` but for consistency with other similar
APIs the name `pluginId` is chosen, and returns e.g. `kwin4_effect_maximize`

scripting/scriptedeffect.cpp

@@ -694,6 +694,11 @@ void ScriptedEffect::animationEnded(KWin::EffectWindow *w, Attribute a, uint met
     emit animationEnded(w, 0);
 }
 
+QString ScriptedEffect::pluginId() const
+{
+    return m_effectName;
+}
+
 bool ScriptedEffect::isActiveFullScreenEffect() const
 {
     return effects->activeFullScreenEffect() == this;

scripting/scriptedeffect.h

@@ -28,6 +28,10 @@ class KWIN_EXPORT ScriptedEffect : public KWin::AnimationEffect
     Q_ENUMS(MetaType)
     Q_ENUMS(EasingCurve)
     Q_ENUMS(SessionState)
+    /**
+     * The plugin ID of the effect
+     */
+    Q_PROPERTY(QString pluginId READ pluginId CONSTANT)
     /**
      * True if we are the active fullscreen effect
      */
@@ -108,6 +112,8 @@ public:
         return m_screenEdgeCallbacks;
     }
 
+    QString pluginId() const;
+
     bool isActiveFullScreenEffect() const;
 
     bool registerTouchScreenCallback(int edge, QScriptValue callback);