Cleanup connection handling in QML

Consistently pass connection objects to files that need them instead of randomly using Controller.activeConnection in some of them

src/qml/Component/ChatBox/ChatBar.qml

@@ -46,6 +46,8 @@ QQC2.Control {
      */
     property alias textField: textField
 
+    property NeoChatConnection connection
+
     /**
      * @brief The list of actions in the ChatBar.
      *
@@ -414,6 +416,7 @@ QQC2.Control {
         y: -height - 5
         z: 1
         chatDocumentHandler: documentHandler
+        connection: root.connection
         Behavior on height {
             NumberAnimation {
                 property: "height"

src/qml/Component/ChatBox/ChatBox.qml

@@ -36,6 +36,8 @@ ColumnLayout {
      */
     required property NeoChatRoom currentRoom
 
+    required property NeoChatConnection connection
+
     /**
      * @brief A message has been sent from the chat bar.
      */
@@ -62,6 +64,8 @@ ColumnLayout {
     ChatBar {
         id: chatBar
 
+        connection: root.connection
+
         visible: root.currentRoom.canSendEvent("m.room.message")
 
         Layout.fillWidth: true

src/qml/Component/ChatBox/CompletionMenu.qml

@@ -17,11 +17,13 @@ QQC2.Popup {
     id: root
     width: parent.width
 
+    required property NeoChatConnection connection
+
     visible: completions.count > 0
 
     RoomListModel {
         id: roomListModel
-        connection: Controller.activeConnection
+        connection: root.connection
     }
 
     property var chatDocumentHandler