fix: Use SignedId instead of regular ID in portal update (#13197)

The Active Storage blob ids were handled inconsistently across the API.

- When a new logo was uploaded, the upload controller returned a
signed_id
- When loading an existing portal that already had a logo, the portal
model returned a blob_id.

This caused the API portal API to fail. There are about 107 instances of
this in production, so this change will fix that.

app/models/portal.rb

@@ -53,7 +53,7 @@ class Portal < ApplicationRecord
       file_type: logo.content_type,
       account_id: account_id,
       file_url: url_for(logo),
-      blob_id: logo.blob_id,
+      blob_id: logo.blob.signed_id,
       filename: logo.filename.to_s
     }
   end