Remove manifest package name

As reported by gradle:

> Setting the namespace via a source AndroidManifest.xml's package
> attribute is deprecated.
>
> Please instead set the namespace (or testNamespace) in the module's
> build.gradle file, as described here:
> https://developer.android.com/studio/build/configure-app-module#set-namespace

server/build.gradle

@@ -1,6 +1,7 @@
 apply plugin: 'com.android.application'
 
 android {
+    namespace 'com.genymobile.scrcpy'
     compileSdkVersion 33
     defaultConfig {
         applicationId "com.genymobile.scrcpy"

server/src/main/AndroidManifest.xml

@@ -1,2 +1,2 @@
 <!-- not a real Android application, it is run by app_process manually -->
-<manifest package="com.genymobile.scrcpy"/>
+<manifest />