Fix download logs button (#1227)

## Problem

The button to download logs does not work. There are two problems:

* `response.blob()` is an asynchronous function, so `createObjectURL`
receives a promise instead of a Blob.
* Fetch returns a successful promise even if the response is not OK. So
the `catch` call does not handle that kind of problem. And, what is
worse, it is hiding the real issue.

## Solution

Wait for `response.blob()` before using its result and log errors in
`catch`.

web/src/client/manager.js

@@ -86,6 +86,10 @@ class ManagerBaseClient {
    */
   async fetchLogs() {
     const response = await fetch(`${this.client.baseUrl}/manager/logs`);
+    if (!response.ok) {
+      throw new Error("Could not fetch the logs");
+    }
+
     return response;
   }
 

web/src/components/core/LogsButton.jsx

@@ -76,9 +76,15 @@ const LogsButton = ({ ...props }) => {
   const collectAndDownload = () => {
     setError(null);
     setIsCollecting(true);
-    cancellablePromise(client.manager.fetchLogs().then(response => URL.createObjectURL(response.blob())))
+    cancellablePromise(
+      client.manager.fetchLogs().then((response) => response.blob()),
+    )
+      .then(URL.createObjectURL)
       .then(autoDownload)
-      .catch(setError)
+      .catch((error) => {
+        console.error(error);
+        setError(true);
+      })
       .finally(() => setIsCollecting(false));
   };