fix: use x-www-form-urlencoded for token exchange requests

packages/hoppscotch-common/src/helpers/oauth.ts

@@ -250,19 +250,23 @@ const handleOAuthRedirect = async () => {
     return E.left("NO_CODE_VERIFIER" as const)
   }
 
-  // Exchange the authorization code for an access token
-  const tokenResponse = await runRequestThroughInterceptor({
-    url: tokenEndpoint,
-    data: JSON.stringify({
+  const data = new URLSearchParams({
     grant_type: "authorization_code",
     code: queryParams.code,
     client_id: clientID,
     client_secret: clientSecret,
     redirect_uri: redirectUri,
     code_verifier: codeVerifier,
-    }),
+  })
+
+  // Exchange the authorization code for an access token
+  const tokenResponse = await runRequestThroughInterceptor({
+    url: tokenEndpoint,
+    data: data.toString(),
     method: "POST",
-    headers: {},
+    headers: {
+      "Content-Type": "application/x-www-form-urlencoded",
+    },
   })
 
   // Clean these up since we don't need them anymore