fix(cloud_firestore, android): suppress unchecked warning (#16979)

Author: SelaseKay

Diff for: packages/cloud_firestore/cloud_firestore/android/src/main/java/io/flutter/plugins/firebase/firestore/FlutterFirebaseFirestoreMessageCodec.java

@@ -244,6 +244,7 @@ protected Object readValueOfType(byte type, ByteBuffer buffer) {
         readAlignment(buffer, 8);
         return new GeoPoint(buffer.getDouble(), buffer.getDouble());
       case DATA_TYPE_VECTOR_VALUE:
+        @SuppressWarnings("unchecked")
         final ArrayList<Double> arrayList = (ArrayList<Double>) readValue(buffer);
         double[] doubleArray = new double[arrayList.size()];
         for (int i = 0; i < arrayList.size(); i++) {