I think it better to use `SchemaType.PROTOBUF` from `import { SchemaType } from 'generated-sources';
` instead of hardcoded value
Impossible to edit Schema of PROTOBUF type
**Describe the bug**
Button Edit Schema redirects to an empty screen.


**Set up**
http://redesign.internal.kafka-ui.provectus.io/


**Steps to Reproduce**
Steps to reproduce the behavior:

1. Click the button Edit Schema for existing proto schema, redirection leads to an empty screen http://redesign.internal.kafka-ui.provectus.io/ui/clusters/local/schemas/proto3/edit
2. Back and Forward buttons in the navigation bar redirect to application`s URLs but the screen is always empty. Only Reload button helps.

**Expected behavior**
Edit screen with Latest schema and New schema like for other types of Schemas i.e. http://redesign.internal.kafka-ui.provectus.io/ui/clusters/local/schemas/json1/edit

**Screenshots**
![image](https://user-images.githubusercontent.com/92585878/145196310-da89179b-04a4-488b-bff4-5e57adfc5171.png)


**Additional context**
Edit schema works correctly for AVRO and JSON schemas types

kafka-ui-react-app/src/components/Schemas/Edit/Edit.tsx
kafka-ui-react-app/src/components/Schemas/Edit/Edit.tsx
diff --git a/kafka-ui-react-app/src/components/Schemas/Edit/Edit.tsx b/kafka-ui-react-app/src/components/Schemas/Edit/Edit.tsx
index 63a48580dca..27a109f0238 100644
--- a/kafka-ui-react-app/src/components/Schemas/Edit/Edit.tsx
+++ b/kafka-ui-react-app/src/components/Schemas/Edit/Edit.tsx
@@ -37,10 +37,11 @@ const Edit: React.FC = () => {
 
   const schema = useAppSelector((state) => selectSchemaById(state, subject));
 
-  const formatedSchema = React.useMemo(
-    () => JSON.stringify(JSON.parse(schema?.schema || '{}'), null, '\t'),
-    [schema]
-  );
+  const formatedSchema = React.useMemo(() => {
+    return schema?.schemaType === SchemaType.PROTOBUF
+      ? schema?.schema
+      : JSON.stringify(JSON.parse(schema?.schema || '{}'), null, '\t');
+  }, [schema]);
 
   const onSubmit = React.useCallback(async (props: NewSchemaSubjectRaw) => {
     if (!schema) return;
