Don't install console panic hook and tracing wasm subscriber in egui_web (#1230)

Do so in egui_demo_app instead

egui_demo_app/src/lib.rs

@@ -13,6 +13,12 @@ use eframe::wasm_bindgen::{self, prelude::*};
 #[cfg(target_arch = "wasm32")]
 #[wasm_bindgen]
 pub fn start(canvas_id: &str) -> Result<(), wasm_bindgen::JsValue> {
+    // Make sure panics are logged using `console.error`.
+    console_error_panic_hook::set_once();
+
+    // Redirect tracing to console.log and friends:
+    tracing_wasm::set_as_global_default();
+
     let app = egui_demo_lib::WrapApp::default();
     eframe::start_web(canvas_id, Box::new(app))
 }