fix(slack): fix download fileName param and canvas error handling

Author: waleedlatif1

apps/sim/blocks/blocks/slack.ts

@@ -1025,10 +1025,10 @@ Return ONLY the timestamp string - no explanations, no quotes, no extra text.`,
 
           case 'download': {
             const fileId = (rest as any).fileId
-            const downloadFileName = (rest as any).downloadFileName
+            const fileName = (rest as any).fileName
             baseParams.fileId = fileId
-            if (downloadFileName) {
-              baseParams.fileName = downloadFileName
+            if (fileName) {
+              baseParams.fileName = fileName
             }
             break
           }

apps/sim/tools/slack/canvas.ts

@@ -90,6 +90,15 @@ export const slackCanvasTool: ToolConfig<SlackCanvasParams, SlackCanvasResponse>
   transformResponse: async (response: Response) => {
     const data = await response.json()
 
+    if (!data.ok) {
+      return {
+        success: false,
+        output: {
+          error: data.error || 'Unknown error',
+        },
+      }
+    }
+
     return {
       success: true,
       output: {