Update 20486C_MOD15_DEMO.md
Update 20486C_MOD15_DEMO.md

Fixed bug: #83723
MicrosoftLearning/20486-DevelopingASPNETMVCWebApplications,MicrosoftLearning/20486-DevelopingASPNETMVCWebApplications,MicrosoftLearning/20486-DevelopingASPNETMVCWebApplications