chore: cleanup as unknown conversion (#19587)

superset-frontend/cypress-base/cypress/utils/parsePostForm.ts

@@ -22,7 +22,7 @@
 export default function parsePostForm(requestBody: ArrayBuffer) {
   type ParsedFields = Record<string, string[] | string>;
   if (requestBody.constructor.name !== 'ArrayBuffer') {
-    return requestBody as unknown as ParsedFields;
+    return requestBody;
   }
   const lines = new TextDecoder('utf-8').decode(requestBody).split('\n');
   const fields: ParsedFields = {};