fix: add flow id when return_to is passed to the verification

[jhonatanhulse]

This pull request basically appends the flow ID when redirecting the user to the passed return_to URL after clicking the verification link.

Related issue(s)

#2481

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 green light (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.

[CLAassistant]

All committers have signed the CLA.

[codecov]

Codecov Report

Merging #2482 (8e37eb6) into master (29e4a51) will increase coverage by 0.02%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master    #2482      +/-   ##
==========================================
+ Coverage   76.50%   76.53%   +0.02%     
==========================================
  Files         317      317              
  Lines       17642    17644       +2     
==========================================
+ Hits        13497    13503       +6     
+ Misses       3209     3205       -4     
  Partials      936      936              

Impacted Files	Coverage Δ
selfservice/flow/verification/flow.go	90.36% <100.00%> (+0.23%)	⬆️
selfservice/strategy/link/strategy_verification.go	56.44% <100.00%> (ø)
cmd/courier/watch.go	76.27% <0.00%> (+6.77%)	⬆️

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[vinckr]

Hello @jhullse
Congrats on merging your first PR in Ory 🎉 !
Your contribution will soon be helping secure millions of identities around the globe 🌏.
As a small token of appreciation we send all our first time contributors a gift package to welcome them to the community.
Please drop me an email and I will forward you the form to claim your Ory swag!