improve mixpanel usage statistics (#2238)

Other changes:
- Always display first start dialog if privacy options are unset (e.g. if the user closed GPT4All without selecting them)
- LocalDocs scanQueue is now always deferred
- Fix a potential crash in magic_match
- LocalDocs indexing is now started after the first start dialog is dismissed so usage stats are included

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

gpt4all-chat/qml/NetworkDialog.qml

@@ -100,16 +100,10 @@ NOTE: By turning on this feature, you will be sending your data to the GPT4All O
     }
 
     onAccepted: {
-        if (MySettings.networkIsActive)
-            return
-        MySettings.networkIsActive = true;
-        Network.sendNetworkToggled(true);
+        MySettings.networkIsActive = true
     }
 
     onRejected: {
-        if (!MySettings.networkIsActive)
-            return
-        MySettings.networkIsActive = false;
-        Network.sendNetworkToggled(false);
+        MySettings.networkIsActive = false
     }
 }