fix: Fix Unable to retrieve jni environment. Is the thread attached? errors by using jni::ThreadScope (#2457)

fix: Add `jni::ThreadScope` to `JVisionCameraScheduler`

Author: mrousavy

package/android/src/main/cpp/frameprocessor/java-bindings/JVisionCameraScheduler.cpp

@@ -21,7 +21,9 @@ void JVisionCameraScheduler::dispatchAsync(const std::function<void()>& job) {
 }
 
 void JVisionCameraScheduler::scheduleTrigger() {
-  // 2. schedule `triggerUI` to be called on the java thread
+  // 2.1 Open a JNI Thread scope because this might be called from a C++ background Thread
+  jni::ThreadScope scope;
+  // 2.2 schedule `triggerUI` to be called on the java thread
   static auto method = _javaPart->getClass()->getMethod<void()>("scheduleTrigger");
   method(_javaPart.get());
 }