chore(gui-client): log entire error when connlib fails (#7273)

The `error_msg` here is already a user-friendly string because we are
also showing it to the user in an error message. These can be entirely
different errors so we should display them as different messages. This
will allow Sentry to group them together correctly.

rust/gui-client/src-common/src/controller.rs

@@ -539,7 +539,7 @@ impl<I: GuiIntegration> Controller<I> {
                         "To access resources, sign in again.",
                     )?;
                 } else {
-                    tracing::error!(?error_msg, "Disconnected");
+                    tracing::error!("Connlib disconnected: {error_msg}");
                     native_dialog::MessageDialog::new()
                         .set_title("Firezone Error")
                         .set_text(&error_msg)