Align OffsetScrolling to zero-based indexes.

Closes: #4673
Original pull request: #4678

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/query/Query.java

@@ -312,7 +312,7 @@ public class Query implements ReadConcernAware, ReadPreferenceAware {
 
 		Assert.notNull(position, "ScrollPosition must not be null");
 
-		this.skip = position.getOffset();
+		this.skip = position.isInitial() ? 0 : position.getOffset() + 1;
 		this.keysetScrollPosition = null;
 		return this;
 	}