Support emptyText for missing referenced entity as well on ReferenceField

[archfz]

Is your feature request related to a problem? Please describe.
I want to display empty text in case where reference is set but the referenced entity is missing. This is easily a case in systems where soft deleting is allowed.

Describe the solution you'd like
For now I am using the same emptyText as is used in the same case where the reference is not set. This works for me, but maybe best is to have a separate prop. Here is the patch:

diff --git a/node_modules/ra-ui-materialui/esm/field/ReferenceField.js b/node_modules/ra-ui-materialui/esm/field/ReferenceField.js
index 3dc814e..f44ccae 100644
--- a/node_modules/ra-ui-materialui/esm/field/ReferenceField.js
+++ b/node_modules/ra-ui-materialui/esm/field/ReferenceField.js
@@ -85,7 +85,7 @@ var ReferenceField = function (props) {
     if (!isReferenceDeclared) {
         throw new Error("You must declare a <Resource name=\"" + props.reference + "\"> in order to use a <ReferenceField reference=\"" + props.reference + "\">");
     }
-    return get(record, source) == null ? (emptyText ? (React.createElement(Typography, { component: "span", variant: "body2" }, emptyText)) : null) : (React.createElement(NonEmptyReferenceField, __assign({}, rest, { record: record, source: source })));
+    return get(record, source) == null ? (emptyText ? (React.createElement(Typography, { component: "span", variant: "body2" }, emptyText)) : null) : (React.createElement(NonEmptyReferenceField, __assign({}, rest, { emptyText, record: record, source: source })));
 };
 ReferenceField.propTypes = {
     addLabel: PropTypes.bool,
@@ -157,7 +157,7 @@ export var ReferenceFieldView = function (props) {
         return React.createElement(LinearProgress, null);
     }
     if (!referenceRecord) {
-        return null;
+        return props.emptyText || null;
     }
     if (resourceLinkPath) {
         return (React.createElement(RecordContextProvider, { value: referenceRecord },

Describe alternatives you've considered
N\A

Additional context
N\A