support_uri validation missing in WARP client for Windows

support_uri parameter in the WARP client local settings file (mdm.xml) lacked proper validation which allowed for privilege escalation and launching an arbitrary executable on the local machine upon clicking on the "Send feedback" option. An attacker with access to the local file system could use a crafted XML config file pointing to a malicious file or set a local path to the executable using Cloudflare Zero Trust Dashboard (for Zero Trust enrolled clients).