Add macOS app icon (#2723)

## Description

<!--
Description and motivation for this PR.

Include 'Fixes #<number>' if this is fixing some issue.
-->

This PR simply adds app icon for `MacOSExample` app.  

## Test plan

<!--
Describe how did you test this change here.
-->

The icon is visible as intended:

- from Xcode

![xcode_icon](https://github.com/software-mansion/react-native-gesture-handler/assets/56112901/2539aca9-47e8-4aad-8998-8f16c9375aa9)
- and from dock

![dock_icon](https://github.com/software-mansion/react-native-gesture-handler/assets/56112901/288e76bf-7bfb-4ad8-869f-d4529cde3d88)

MacOSExample/macos/MacOSExample-macOS/Assets.xcassets/AppIcon.appiconset/Contents.json

@@ -1,51 +1,61 @@
 {
   "images" : [
     {
+      "filename" : "16.png",
       "idiom" : "mac",
       "scale" : "1x",
       "size" : "16x16"
     },
     {
+      "filename" : "32 1.png",
       "idiom" : "mac",
       "scale" : "2x",
       "size" : "16x16"
     },
     {
+      "filename" : "32.png",
       "idiom" : "mac",
       "scale" : "1x",
       "size" : "32x32"
     },
     {
+      "filename" : "64.png",
       "idiom" : "mac",
       "scale" : "2x",
       "size" : "32x32"
     },
     {
+      "filename" : "128.png",
       "idiom" : "mac",
       "scale" : "1x",
       "size" : "128x128"
     },
     {
+      "filename" : "256 1.png",
       "idiom" : "mac",
       "scale" : "2x",
       "size" : "128x128"
     },
     {
+      "filename" : "256.png",
       "idiom" : "mac",
       "scale" : "1x",
       "size" : "256x256"
     },
     {
+      "filename" : "512 1.png",
       "idiom" : "mac",
       "scale" : "2x",
       "size" : "256x256"
     },
     {
+      "filename" : "512.png",
       "idiom" : "mac",
       "scale" : "1x",
       "size" : "512x512"
     },
     {
+      "filename" : "1024.png",
       "idiom" : "mac",
       "scale" : "2x",
       "size" : "512x512"

MacOSExample/macos/MacOSExample-macOS/Base.lproj/Main.storyboard

@@ -1,8 +1,8 @@
 <?xml version="1.0" encoding="UTF-8"?>
-<document type="com.apple.InterfaceBuilder3.Cocoa.Storyboard.XIB" version="3.0" toolsVersion="21701" targetRuntime="MacOSX.Cocoa" propertyAccessControl="none" useAutolayout="YES">
+<document type="com.apple.InterfaceBuilder3.Cocoa.Storyboard.XIB" version="3.0" toolsVersion="22505" targetRuntime="MacOSX.Cocoa" propertyAccessControl="none" useAutolayout="YES">
     <dependencies>
         <deployment identifier="macosx"/>
-        <plugIn identifier="com.apple.InterfaceBuilder.CocoaPlugin" version="21701"/>
+        <plugIn identifier="com.apple.InterfaceBuilder.CocoaPlugin" version="22505"/>
     </dependencies>
     <scenes>
         <!--Application-->