Android: update Android Jar build.gradle file to AGP 8

To allow building and developing from Android Studio and get rid of
warnings.

Change-Id: I5f896a270917120f98eefd2f4aa449714451f994
Reviewed-by: Tinja Paavoseppä <tinja.paavoseppa@qt.io>

src/android/jar/build.gradle

@@ -7,7 +7,7 @@ buildscript {
     }
 
     dependencies {
-        classpath 'com.android.tools.build:gradle:7.0.2'
+        classpath 'com.android.tools.build:gradle:8.0.2'
     }
 }
 
@@ -23,12 +23,11 @@ repositories {
 }
 
 android {
-    compileSdkVersion 33
-    buildToolsVersion "33.0.3"
+    compileSdk 33
+    namespace "org.qtproject.qt.android"
 
     defaultConfig {
         minSdkVersion 23
-        targetSdkVersion 33
     }
 
     sourceSets {