Incorrect FieldsService updateField example

[br41nslug]

As pointed out in this issue directus/directus#25279 the following service usage example is incorrect:

https://directus.io/docs/guides/extensions/api-extensions/services#update-a-field

Correct usage:

const data = await fieldsService.updateField('collection_name', {
    field: 'field_name',
    meta: {
        icon: 'title',
    },
});

[linear]

EDU-398 Incorrect FieldsService updateField example