Fix potential NullPointerException in ParameterMetadataProvider.

We now guard against null values returned from ParameterExpression.getJavaType() before inspecting the value further as it turns out that Class.isAssignableFrom(…) chokes on null values being passed.

Looks like Hibernate six returns null in scenarios it previously didn't.

spring-data-jpa/src/main/java/org/springframework/data/jpa/repository/query/ParameterMetadataProvider.java

@@ -237,6 +237,10 @@ class ParameterMetadataProvider {
 
 			Class<? extends T> expressionType = expression.getJavaType();
 
+			if (expressionType == null) {
+				return value;
+			}
+
 			if (String.class.equals(expressionType)) {
 
 				switch (type) {