fix: allow custom schema formats without validation error

The parser now accepts any string schema format as valid, aligning with the AsyncAPI spec which states custom formats are allowed with optional implementation. Unknown formats are passed through without modification instead of throwing an error.

Author: shwetd19

packages/parser/src/schema-parser/index.ts

@@ -46,10 +46,21 @@ export async function validateSchema(parser: Parser, input: ValidateSchemaInput)
 }
 
 export async function parseSchema(parser: Parser, input: ParseSchemaInput) {
+  // First validate that format is a string
+  if (typeof input.schemaFormat !== 'string') {
+    throw new Error('Schema format must be a string');
+  }
+
   const schemaParser = parser.parserRegistry.get(input.schemaFormat);
+  
   if (schemaParser === undefined) {
-    throw new Error('Unknown schema format');
+    // Simply return the schema as-is for unknown formats
+    return {
+      parsed: input.data, // Assuming you meant to return input.data instead of input.schema
+      format: input.schemaFormat
+    };
   }
+  
   return schemaParser.parse(input);
 }