fix: update feedback & reset file input

[mrv777]

Description

• This should fix the errors so that file upload events are properly passed and the function doesn't error out, resulting in accurate feedback and a refresh on www upload success
• The also resets the file inputs on upload which should resolve issue Browsing for update file disallowed after unsuccessful initial attempt #518

[tdb3]

Post merge test results:

• Attempting to use a dummy.bin file for either firmware or website resulted in an error toast (expected)
• 2nd attempt to browse now works well (able to select file)
• Updated firmware with esp-miner.bin. Observed the percentage completion (nice!). Received the success toast.
• Updated website with www.bin. Observed the percentage completion. Received the success toast and the page refreshed

Great work!