fix: check the content type for the file when uploading from cloud storage (#5378)

When sending the message with audio, only the signed id of the file is sent.
In the back end check only the UploadedFile type.
The attachment has the default file type image, now it gets the content type from the signed id

Fixes: #5375

Co-authored-by: Sojan Jose <sojan@pepalo.com>

app/builders/messages/message_builder.rb

@@ -35,7 +35,13 @@ class Messages::MessageBuilder
         file: uploaded_attachment
       )
 
-      attachment.file_type = file_type(uploaded_attachment&.content_type) if uploaded_attachment.is_a?(ActionDispatch::Http::UploadedFile)
+      attachment.file_type = if uploaded_attachment.is_a?(String)
+                               file_type_by_signed_id(
+                                 uploaded_attachment
+                               )
+                             else
+                               file_type(uploaded_attachment&.content_type)
+                             end
     end
   end
 

app/helpers/file_type_helper.rb

@@ -8,6 +8,12 @@ module FileTypeHelper
     :file
   end
 
+  # Used in case of DIRECT_UPLOADS_ENABLED=true
+  def file_type_by_signed_id(signed_id)
+    blob = ActiveStorage::Blob.find_signed(signed_id)
+    file_type(blob&.content_type)
+  end
+
   def image_file?(content_type)
     [
       'image/jpeg',