Fix no blinking cursor on search field at start up
Fix bug 417213 by adding Timer in SearchField and moving searchField.forceActiveFocus() call to said Timer because searchField.forceActiveFocus() call in Component.onCompleted() doesn't trigger active focus.
This fix only enable blinking cursor at start up so if users click other menu such as installed, the blinking cursor will not appear but the users can type to the search field.