fix: accept login_challenge after verification

[hperl]

Related issue(s)

Checklist

• I have read the contributing guidelines.
• I have referenced an issue containing the design document if my change
  introduces a new feature.
• I am following the
  contributing code guidelines.
• I have read the security policy.
• I confirm that this pull request does not address a security
  vulnerability. If this pull request addresses a security vulnerability, I
  confirm that I got the approval (please contact
  security@ory.sh) from the maintainers to push
  the changes.
• I have added tests that prove my fix is effective or that my feature
  works.
• I have added or changed the documentation.

Further Comments

[codecov]

Codecov Report

Merging #3427 (e6b5832) into master (76241be) will decrease coverage by 0.42%.
Report is 1 commits behind head on master.
The diff coverage is 47.61%.

❗ Current head e6b5832 differs from pull request most recent head 5e8c5eb. Consider uploading reports for the commit 5e8c5eb to get more accurate results

@@            Coverage Diff             @@
##           master    #3427      +/-   ##
==========================================
- Coverage   78.44%   78.03%   -0.42%     
==========================================
  Files         327      327              
  Lines       21783    21402     -381     
==========================================
- Hits        17088    16700     -388     
- Misses       3461     3465       +4     
- Partials     1234     1237       +3     

Files Changed	Coverage Δ
selfservice/flow/flow.go	100.00% <ø> (ø)
selfservice/flow/verification/flow.go	92.00% <ø> (ø)
selfservice/flow/verification/handler.go	57.69% <15.38%> (-5.34%)	⬇️
selfservice/flow/registration/flow.go	97.43% <100.00%> (+0.06%)	⬆️
selfservice/flow/registration/hook.go	71.52% <100.00%> (+0.19%)	⬆️
selfservice/hook/verification.go	76.74% <100.00%> (+1.13%)	⬆️
session/handler.go	68.60% <100.00%> (ø)

... and 3 files with indirect coverage changes