chore(preprod): Slightly improve error UI for size upload failure case (#101086)

Closes
https://linear.app/getsentry/issue/EME-395/improve-error-handling-for-failed-upload-case-not-size-error-but

We should show the message related to the error for the user's improved
comprehension

Before:
<img width="1395" height="1198" alt="Screenshot 2025-10-07 at 9 26
10 AM"
src="https://github.com/user-attachments/assets/9c12f1a5-4166-4539-a203-995785da8716"
/>

After:
<img width="1276" height="1116" alt="image"
src="https://github.com/user-attachments/assets/7025d74a-9e34-47f6-bb41-3754cbb03ca0"
/>

Author: NicoHinderling

static/app/views/preprod/buildDetails/buildDetails.tsx

@@ -118,8 +118,9 @@ export default function BuildDetails() {
           <BuildError
             title="Build details unavailable"
             message={
-              buildDetailsQuery.error?.message ||
-              'Unable to load build details for this artifact' // TODO(preprod): translate once we have a final design
+              typeof buildDetailsQuery.error?.responseJSON?.error === 'string'
+                ? buildDetailsQuery.error?.responseJSON.error
+                : 'Unable to load build details for this artifact' // TODO(preprod): translate once we have a final design
             }
           />
         </Layout.Page>