fixing password encoding in local storage

[DGoiana]

Closes #1244
We were not storing our passwords correctly, so when trying to retrieve it, decode would actually return null

Review checklist

• Terms and conditions reflect the current change
• Contains enough appropriate tests
• If aimed at production, writes a new summary in whatsnew/whatsnew-pt-PT
• Properly adds an entry in changelog.md with the change
• If PR includes UI updates/additions, its description has screenshots
• Behavior is as expected
• Clean, well-structured code

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 2 lines in your changes missing coverage. Please review.

Project coverage is 17%. Comparing base (36b0f44) to head (5477255).

Additional details and impacted files

@@           Coverage Diff           @@
##           develop   #1245   +/-   ##
=======================================
+ Coverage       17%     17%   +1%     
=======================================
  Files          229     229           
  Lines         6952    6952           
=======================================
+ Hits          1147    1154    +7     
+ Misses        5805    5798    -7     

[limwa]

Why was this removed?

[thePeras]

I think is to sentry catch the error

[limwa]

Why is this a relevant error for sentry to catch? This happens if the password was encrypted with a different key/IV - we changed it ourselves - or if the store gets miraculously corrupted - unlikely. But in either case, we just want the user to perform login again, no?
Either way, if we wanted the exception to go to sentry, wouldn't it be better to add the code in the catch block to report the exception and return null either way?

[LuisDuarte1]

Instead of "encrypting" the password (which is not encryption but just obfuscation) we should focus on supporting flutter_secure_storage and remove this step.

[limwa]

Yep, I agree. I suggested that on Slack and I think it's the way to go! What do the others think?