Changing registration changelog to include username

[srijeet0406]

This PR is not related to any issue. It fixes the changelog entry to include the username instead of email twice, when a registration is sent to a user.

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Which Traffic Control components are affected by this PR?

• Traffic Ops

What is the best way to verify this PR?

Send a user registration email on TO/ TP and make sure the corresponding changelog shows the correct username for the user, instead of email.

If this is a bugfix, which Traffic Control versions contained the bug?

• master

PR submission checklist

• This PR has tests
• This PR has documentation
• This PR has a CHANGELOG.md entry
• This PR DOES NOT FIX A SERIOUS SECURITY VULNERABILITY (see the Apache Software Foundation's security guidelines for details)

[codecov]

Codecov Report

Merging #7511 (ec56d17) into master (1c11f7f) will increase coverage by 2.57%.
The diff coverage is 0.00%.

@@             Coverage Diff              @@
##             master    #7511      +/-   ##
============================================
+ Coverage     27.60%   30.17%   +2.57%     
  Complexity       98       98              
============================================
  Files           686      789     +103     
  Lines         77933    82299    +4366     
  Branches         90      815     +725     
============================================
+ Hits          21513    24834    +3321     
- Misses        54400    55386     +986     
- Partials       2020     2079      +59     

Flag	Coverage Δ
golib_unit	48.58% <ø> (+0.01%)	⬆️
grove_unit	4.60% <ø> (ø)
t3c_unit	5.32% <ø> (ø)
traffic_monitor_unit	21.28% <ø> (ø)
traffic_ops_integration	69.42% <ø> (ø)
traffic_ops_unit	23.14% <0.00%> (-0.01%)	⬇️
traffic_portal_v2	76.08% <ø> (?)
traffic_stats_unit	10.14% <ø> (ø)
unit_tests	27.23% <0.00%> (+2.99%)	⬆️
v3	57.79% <ø> (ø)
v4	79.18% <ø> (ø)
v5	78.63% <ø> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
traffic_ops/traffic_ops_golang/login/register.go	0.00% <0.00%> (ø)

... and 105 files with indirect coverage changes

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[rimashah25]

Code changes LGTM. I tested it locally and now the change log messages show username as registration_random_alphanumeric_characters instead of email or empty

[rimashah25]

LGTM. All works correctly. Failing TPv1 and TPv2 tests have nothing to do with this PR.