Added more spotify error handling

[HyungnaLim]

Added if-else statements on search_result.html to handle errors from reading track information when there's no or less than 3 top tracks. Also, artist image will not appear if there's no artist image url found from api. When there's no genre, a message will be displayed instead of leaving the section empty. All data will be returned as None if they are not found from api.

Example search result of no artist image, no genre, only one track:

[HyungnaLim]

Note: This is a sub branch from db_data_handling!

[HyungnaLim]

I won't make more change for this branch from now! So, it's ready for final review

[rwalk651]

Changed base to main since db_data_handling was merged.