Amend "effects/Overview: Use SearchField from PlasmaExtras"

This commit amends 4eefd27f.

Changes were pushed to the wrong branch, so the MR got merged not in its
final state.

(cherry picked from commit 574b51f0)

src/effects/overview/qml/ScreenView.qml

@@ -203,8 +203,6 @@ FocusScope {
                     anchors.centerIn: parent
                     width: Math.min(parent.width, 20 * PlasmaCore.Units.gridUnit)
                     focus: true
-                    placeholderText: i18nd("kwin_effects", "Search...")
-                    clearButtonShown: true
                     Keys.priority: Keys.BeforeItem
                     Keys.forwardTo: text && heap.count === 0 ? searchResults : heap
                     onTextChanged: {