fix: retry window fetching (#1291)

Description
---
Seeing errors in Sentry where the main window can't be fetched. Retry
for a second before panic'ing.

Motivation and Context
---
A brief delay between window creation and closing may help alleviate the
error.

How Has This Been Tested?
---
Error isn't present locally so 🤞🏻

src-tauri/src/commands.rs

@@ -143,12 +143,28 @@ pub struct SignWsDataResponse {
 
 #[tauri::command]
 pub async fn close_splashscreen(app: tauri::AppHandle) {
-    let splashscreen_window = app
-        .get_webview_window("splashscreen")
-        .expect("no window labeled 'splashscreen' found");
-    let main_window = app
-        .get_webview_window("main")
-        .expect("no window labeled 'main' found");
+    let close_max_retries: u32 = 10; // Maximum number of retries
+    let retry_delay_ms: u64 = 100; // Delay between retries in milliseconds
+
+    let mut retries = 0;
+
+    let (splashscreen_window, main_window) = loop {
+        let splashscreen_window = app.get_webview_window("splashscreen");
+        let main_window = app.get_webview_window("main");
+
+        if let (Some(splashscreen), Some(main)) = (splashscreen_window, main_window) {
+            break (splashscreen, main);
+        }
+
+        retries += 1;
+        if retries >= close_max_retries {
+            error!(target: "LOG_TARGET", "Failed to fetch both 'splashscreen' and 'main' windows after {} retries", close_max_retries);
+            return;
+        }
+
+        info!(target: "LOG_TARGET", "Failed to fetch both 'splashscreen' and 'main' windows. Retrying in {}ms", retry_delay_ms);
+        tokio::time::sleep(Duration::from_millis(retry_delay_ms)).await;
+    };
 
     if let (Ok(window_position), Ok(window_size)) = (
         splashscreen_window.outer_position(),
@@ -170,6 +186,7 @@ pub async fn close_splashscreen(app: tauri::AppHandle) {
         main_window.show().expect("could not show");
     }
 }
+
 #[tauri::command]
 pub async fn download_and_start_installer(
     _missing_dependency: ExternalDependency,