Change credentials storage to FlutterSecureStorage and remove WillPopScope

[Sanat2002]

Issue #[873,851]
The WillPopScope is removed from the first route and the userCrendentials are secured utilizing flutter secure storage , all read and delete operations on the userCrendentials have been modified accordingly.

[bdmendes]

Hey @Sanat2002,
Thank you very much for your contribution. I'll let the CI run as a first step.
About the code, can you remove the comments, and avoid the bang operator?
About the PR description, please follow the template. You can see examples in open PRs in this repo.

[Sanat2002]

Changed the flutter secure storage version. Review this one again so I can fix the problem if it is generated again.

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

[Sanat2002]

Removed the unused import . Run the check again please

[bdmendes]

@Sanat2002 you can edit the original PR comment instead of creating a new one.

[codecov]

Codecov Report

Merging #935 (7209a13) into develop (683a6a8) will increase coverage by 1%.
Report is 1 commits behind head on develop.
The diff coverage is 0%.

Additional details and impacted files

@@          Coverage Diff           @@
##           develop   #935   +/-   ##
======================================
+ Coverage       22%    22%   +1%     
======================================
  Files          136    136           
  Lines         3549   3537   -12     
======================================
  Hits           761    761           
+ Misses        2788   2776   -12     

[bdmendes]

As a side advice, it's best not to fix two unrelated issues in the same PR like this. It makes it more difficult to reason about the changes.

[bdmendes]

The secure credentials are working well, however there is still an exit confirmation on the app. Search for WillPopScope

[bdmendes]

Dear @Sanat2002, we'll be working on this due to the lack of activity. Thanks for your contribution!