chat: fix issues with the initial "New Chat" (#2330)

* select the existing new chat if there already is one when "New Chat" is clicked
* scroll to the new chat when "New Chat" is clicked
* fix the "New Chat" being scrolled past the top of the chat list

Signed-off-by: Jared Van Bortel <jared@nomic.ai>

gpt4all-chat/qml/ChatDrawer.qml

@@ -39,7 +39,8 @@ Rectangle {
             text: qsTr("\uFF0B New chat")
             Accessible.description: qsTr("Create a new chat")
             onClicked: {
-                ChatListModel.addChat();
+                ChatListModel.addChat()
+                conversationList.positionViewAtIndex(0, ListView.Beginning)
                 Network.trackEvent("new_chat", {"number_of_chats": ChatListModel.count})
             }
         }
@@ -60,6 +61,9 @@ Rectangle {
                 anchors.fill: parent
                 anchors.rightMargin: 10
                 model: ChatListModel
+
+                Component.onCompleted: ChatListModel.loadChats()
+
                 ScrollBar.vertical: ScrollBar {
                     parent: conversationList.parent
                     anchors.top: conversationList.top