Remove accidental org.jetbrains:annotations usage.

See spring-projects/spring-data-build#2670

Author: mp911de

spring-data-cassandra/src/main/java/org/springframework/data/cassandra/core/CassandraPersistentEntitySchemaCreator.java

@@ -23,8 +23,6 @@
 import java.util.Set;
 import java.util.stream.Collectors;
 
-import org.jetbrains.annotations.NotNull;
-
 import org.springframework.data.cassandra.core.cql.generator.CqlGenerator;
 import org.springframework.data.cassandra.core.cql.keyspace.CreateIndexSpecification;
 import org.springframework.data.cassandra.core.cql.keyspace.CreateTableSpecification;
@@ -221,7 +219,6 @@ public boolean add(CqlIdentifier cqlIdentifier) {
 			return false;
 		}
 
-		@NotNull
 		@Override
 		public Iterator<CqlIdentifier> iterator() {
 

spring-data-cassandra/src/main/java/org/springframework/data/cassandra/core/mapping/EmbeddedEntityOperations.java

@@ -25,7 +25,6 @@
 import java.util.Spliterator;
 import java.util.function.Consumer;
 
-import org.jetbrains.annotations.NotNull;
 import org.jspecify.annotations.Nullable;
 import org.springframework.beans.BeansException;
 import org.springframework.context.ApplicationContext;
@@ -307,7 +306,6 @@ public CassandraPersistentProperty getProperty(Parameter<?, CassandraPersistentP
 			return property == null ? null : wrap(property);
 		}
 
-		@NotNull
 		@Override
 		public Iterator<CassandraPersistentProperty> iterator() {