qml: don't determine channel state on gui string, use state enum instead

electrum/gui/qml/components/ChannelDetails.qml

@@ -72,7 +72,7 @@ Pane {
 
                     Label {
                         text: channeldetails.state
-                        color: channeldetails.state == 'OPEN'
+                        color: channeldetails.stateCode == ChannelDetails.Open
                                 ? constants.colorChannelOpen
                                 : Material.foreground
                     }

electrum/gui/qml/components/controls/ChannelDelegate.qml

@@ -79,7 +79,7 @@ ItemDelegate {
                 font.pixelSize: constants.fontSizeMedium
                 color: _closed
                         ? constants.mutedForeground
-                        : model.state == 'OPEN'
+                        : model.state_code == ChannelDetails.Open
                             ? constants.colorChannelOpen
                             : Material.foreground
             }

electrum/gui/qml/qechanneldetails.py

@@ -17,6 +17,7 @@ class QEChannelDetails(QObject, QtEventListener):
     _logger = get_logger(__name__)
 
     class State: # subset, only ones we currently need in UI
+        Open = ChannelState.OPEN
         Closed = ChannelState.CLOSED
         Redeemed = ChannelState.REDEEMED