Release boot session data during Netplay cleanup

Boot session data is already handled when the game is booted so this is just fallback in case the game launch fails in some weird way.

Add missing @Keep annotations to functions called from C++

Source/Android/jni/NetPlay/Netplay.cpp

@@ -8,6 +8,7 @@
 #include <jni.h>
 
 #include "Common/CommonTypes.h"
+#include "Core/Boot/Boot.h"
 #include "Core/Config/NetplaySettings.h"
 #include "Core/NetPlayClient.h"
 #include "UICommon/GameFile.h"
@@ -166,6 +167,15 @@ Java_org_dolphinemu_dolphinemu_features_netplay_Netplay_Join(JNIEnv* env, jclass
   return reinterpret_cast<jlong>(client);
 }
 
+JNIEXPORT void JNICALL
+Java_org_dolphinemu_dolphinemu_features_netplay_Netplay_ReleaseBootSessionData(JNIEnv* env, jclass)
+{
+  auto* data = reinterpret_cast<BootSessionData*>(
+      env->GetStaticLongField(IDCache::GetNetplayClass(), IDCache::GetNetplayBootSessionDataPointer()));
+  delete data;
+  env->SetStaticLongField(IDCache::GetNetplayClass(), IDCache::GetNetplayBootSessionDataPointer(), 0);
+}
+
 JNIEXPORT void JNICALL
 Java_org_dolphinemu_dolphinemu_features_netplay_Netplay_ReleaseNetplayClient(JNIEnv* env, jclass)
 {