[PM-3561] Clean the return url of any whitespace

[kspearrin]

Type of change

- [x] Bug fix
- [ ] New feature development
- [ ] Tech debt (refactoring, code cleanup, dependency upgrades, etc)
- [ ] Build/deploy pipeline (DevOps)
- [ ] Other

Objective

Resolves potential security issues related to whitespace allowing open redirects with the SSO return URL.

Code changes

• AccountController.cs: Clean the return url of any whitespace characters, such as space and tab.

Before you submit

• Please check for formatting errors (dotnet format --verify-no-changes) (required)
• If making database changes - make sure you also update Entity Framework queries and/or migrations
• Please add unit tests where it makes sense to do so (encouraged but not required)
• If this change requires a documentation update - notify the documentation team
• If this change has particular deployment requirements - notify the DevOps team

[codecov]

Codecov Report

Attention: 3 lines in your changes are missing coverage. Please review.

Comparison is base (88befc3) 0.00% compared to head (ed68f9a) 32.56%.

❗ Current head ed68f9a differs from pull request most recent head c22d52f. Consider uploading reports for the commit c22d52f to get more accurate results

Files	Patch %	Lines
test/Core.Test/Utilities/CoreHelpersTests.cs	0.00%	3 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff            @@
##           main    #3696       +/-   ##
=========================================
+ Coverage      0   32.56%   +32.56%     
=========================================
  Files         0     1213     +1213     
  Lines         0    63480    +63480     
  Branches      0     4780     +4780     
=========================================
+ Hits          0    20674    +20674     
- Misses        0    41843    +41843     
- Partials      0      963      +963     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[ike-kottlowski]

One question about other whitespace encodings.

[bitwarden-bot]

Checkmarx One – Scan Summary & Details – f6144430-a98a-473a-83b4-218ade49449d

No New Or Fixed Issues Found

[withinfocus]

Solid, but maybe throw in some tests.