Fix BeanIntrospection to handle primitive types in property lookup

Fixes #12079

- Added helper methods isAssignableFrom() and getWrapperType() to properly handle primitive-to-wrapper type conversion
- Updated getProperty(), getReadProperty(), and getWriteProperty() methods to use the new helper
- Primitive types are now converted to their wrapper equivalents before assignability checking
- Resolves IntrospectionException when using Micronaut Mapper with primitive types

All existing mapper tests pass with no regressions.

Author: yashdoshi

core/src/main/java/io/micronaut/core/beans/BeanIntrospection.java

@@ -304,7 +304,7 @@ default <P> BeanWriteProperty<T, P> getRequiredWriteProperty(@NonNull String nam
         ArgumentUtils.requireNonNull("type", type);
 
         final BeanProperty<T, ?> prop = getProperty(name).orElse(null);
-        if (prop != null && type.isAssignableFrom(prop.getType())) {
+        if (prop != null && isAssignableFrom(type, prop.getType())) {
             //noinspection unchecked
             return Optional.of((BeanProperty<T, P>) prop);
         }
@@ -324,7 +324,7 @@ default <P> BeanWriteProperty<T, P> getRequiredWriteProperty(@NonNull String nam
         ArgumentUtils.requireNonNull("type", type);
 
         final BeanReadProperty<T, ?> prop = getReadProperty(name).orElse(null);
-        if (prop != null && type.isAssignableFrom(prop.getType())) {
+        if (prop != null && isAssignableFrom(type, prop.getType())) {
             //noinspection unchecked
             return Optional.of((BeanReadProperty<T, P>) prop);
         }
@@ -345,7 +345,7 @@ default <P> BeanWriteProperty<T, P> getRequiredWriteProperty(@NonNull String nam
         ArgumentUtils.requireNonNull("type", type);
 
         final BeanWriteProperty<T, ?> prop = getWriteProperty(name).orElse(null);
-        if (prop != null && type.isAssignableFrom(prop.getType())) {
+        if (prop != null && isAssignableFrom(type, prop.getType())) {
             //noinspection unchecked
             return Optional.of((BeanProperty<T, P>) prop);
         }
@@ -490,4 +490,35 @@ interface Builder<T> {
          */
         @NonNull T build(Object... params);
     }
+
+    /**
+     * Helper method to check if a source type is assignable to a target type,
+     * properly handling primitive types by converting them to their wrapper types.
+     *
+     * @param targetType The target type to check assignability to
+     * @param sourceType The source type to check assignability from
+     * @return true if the source type is assignable to the target type
+     */
+    static boolean isAssignableFrom(Class<?> targetType, Class<?> sourceType) {
+        Class<?> actualSourceType = sourceType.isPrimitive() ? getWrapperType(sourceType) : sourceType;
+        return targetType.isAssignableFrom(actualSourceType);
+    }
+
+    /**
+     * Helper method to get the wrapper type for a primitive type.
+     *
+     * @param primitiveType The primitive type
+     * @return The corresponding wrapper type, or the original type if not primitive
+     */
+    static Class<?> getWrapperType(Class<?> primitiveType) {
+        if (primitiveType == boolean.class) return Boolean.class;
+        if (primitiveType == byte.class) return Byte.class;
+        if (primitiveType == char.class) return Character.class;
+        if (primitiveType == short.class) return Short.class;
+        if (primitiveType == int.class) return Integer.class;
+        if (primitiveType == long.class) return Long.class;
+        if (primitiveType == float.class) return Float.class;
+        if (primitiveType == double.class) return Double.class;
+        return primitiveType; // Not a primitive, return as-is
+    }
 }