IFC request fails due to proxy issue

[tdipisa]

Description

From what done in #10505
it seems there is a wrong/not proper check in preflight request made in certain condition to determine if the MS proxy need to be used.

From a recent check made on the following context map
https://dev-mapstore.geosolutionsgroup.com/mapstore/#/context/demo_context/46500

it seems the following request to retrieve the IFC model layer fails the first time because CORS are not enabled on the source
https://smart.comune.genova.it/sit/248/o1/Fontane_Marose_IFCgeoref/FontaneMarosegeoreferenziato.ifc

but then the resource trough the MS proxy is not performed

How to reproduce

• Open https://dev-mapstore.geosolutionsgroup.com/mapstore/#/context/demo_context/46500
• Switch to 3D mode

Expected Result

The MS proxy is properly used when necessary as requested by #10505

Current Result

Under certain conditions not identified during development and/or first functional tests the request through the proxy is not performed as expected.

• Not browser related

Browser info

(use this site: https://www.whatsmybrowser.org/ for non expert users)

Browser Affected	Version
Internet Explorer
Edge
Chrome
Firefox
Safari

Other useful information