[feat] handling loading state

[sonigeez]

• used 2 value notifier to update value
• used ShellLinesController to listen values in shell
• used regex to get percentage
• sometime yt-dlp gets more than 100% for some reason, so i have used a if condition to restrict value to be less than 100 https://github.com/championswimmer/yt_dlp_gui/assets/114856815/43741c97-61e9-4e86-8ab8-248648884b2b