chore: Update to 5.3 SDK

UI/MediaGallery/src/Directory.Build.props

@@ -12,12 +12,4 @@
     -->
     <NoWarn>$(NoWarn);NU1507;NETSDK1201;PRI257</NoWarn>
   </PropertyGroup>
-
-  <!-- See https://aka.platform.uno/using-uno-sdk#implicit-packages for more information regarding the Implicit Packages version properties. -->
-  <PropertyGroup>
-    <UnoExtensionsVersion>4.1.24</UnoExtensionsVersion>
-    <UnoToolkitVersion>6.0.24</UnoToolkitVersion>
-    <UnoThemesVersion>5.0.13</UnoThemesVersion>
-    <UnoCSharpMarkupVersion>5.2.14</UnoCSharpMarkupVersion>
-  </PropertyGroup>
 </Project>

UI/MediaGallery/src/global.json

@@ -1,6 +1,6 @@
 {
   // To update the version of Uno please update the version of the Uno.Sdk here. See https://aka.platform.uno/upgrade-uno-packages for more information.
   "msbuild-sdks": {
-    "Uno.Sdk": "5.2.161"
+    "Uno.Sdk": "5.3.99"
   }
 }