Refactor SelectIModel in desktop-viewer-test app

[AnDuong249]

• Fix the download progress not showing due to it not being calculated as a percentage in useDownload.tsx and useProgress.tsx
• Refactored SelectIModel.tsx and BriefcaseStatus.tsx
• Added functions to do file checks in the backend to make sure the file in recents section exists before opening a briefcase connection/navigate to the viewer.
• Checks if file exists before navigating to the file in SelectIModel.tsx and Recents.tsx.
• If the file is deleted, the backend will set the path to empty string, which disables the link in recent sections in Home page/prompts the user to download again in SelectIModel page.
• Extract all the userSettings handling from App.tsx to SettingsContextProvider in SettingsContext. Added a useEffect in the SettingsContextProvider to fetch the latest user settings whenever the url/location changes to make sure each page is rendered with the recent user settings.