fix(cli): removed alpha channel from default IOS AppIcons (#10114)

* bug: removed alpha channel from default IOS AppIcons

According to Apple's human interface guideline
(https://developer.apple.com/design/human-interface-guidelines/app-icons)
transparent or icons with alpha channel are not allowed, and will be rejected
upon upload to Apple appstore.

* Update .changes/ios-non-transparent-icons.md

.changes/ios-non-transparent-icons.md

@@ -0,0 +1,9 @@
+---
+"@tauri-apps/cli": patch:bug
+"tauri-cli": patch:bug
+---
+
+Removed alpha channel from default icons in iOS template to comply with Apple's human interface guideline
+(https://developer.apple.com/design/human-interface-guidelines/app-icons), because
+transparent icons with alpha channel are not allowed, and will be rejected
+upon upload to Apple appstore.