pdf file preview on incident view page

PS:
beter to show as same as image preview

**steps**
1. Goto review page
2. open an incident
3. attach a image (jpg, png)
4. obeserve image thumbnail view
5. observe the process of click on 'view' button
6. redo the steps from '3' with pdf file

Start at the review page's incident view and reproduce the image and PDF attachment flows described in the steps. Compare the existing image thumbnail and View button behavior, then make PDF attachments provide the same preview experience. Done means a PDF shows a thumbnail and opens from View consistently with image attachments.

Written by the indexing model from the issue text.