DolphinView: get rid of writeStateChanged signal in setActive()

DolphinView: get rid of writeStateChanged signal in setActive()

The signal writeStateChanged() was not working because it is not connected
to slotWriteStateChanged() slots when the active view changes. Replace the
signal with direct calls to the slots.

Also, do not delay openRequest signal in DolphinSearchBox::slotSearchTextChanged.
It's no longer required.

BUG: 440366