Prevent empty password being passed into share creation

We already generate a new password when the share password dialog is
created, so there is really no need to clear the field when it closes.
This prevents the field being cleared before the password is sent into
the C++ code, leading to no password actually being sent to the server

Signed-off-by: Claudio Cambra <claudio.cambra@nextcloud.com>

src/gui/filedetails/ShareView.qml

@@ -97,7 +97,6 @@ ColumnLayout {
 
         visible: false
         onAboutToShow: dialogPasswordField.text = shareModel.generatePassword()
-        onClosed: dialogPasswordField.text = ""
 
         onAccepted: {
             if(sharee) {