Fix null safety in flutter in flutter 3.0.5

I upgraded my flutter version to 3.0.5 after that it is showing errors. I fixed many errors of null safety. But still it has some.

please let me know if you can fix.

Please write IHC in your bid.

code - https://www.mediafire.com/file/mqqcklr7kr082pv/User+app+and+web+3.zip/file