templates/macros: rm spurious username duplication

[agoujot]

Stuff I left in #545 (did some behaviour change? idk. I do remember testing, but shrug anyways.)

Bug: T410391

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 69.49%. Comparing base (4b8eb28) to head (3629639).
⚠️ Report is 197 commits behind head on main.

Additional details and impacted files

@@             Coverage Diff              @@
##               main     #586      +/-   ##
============================================
- Coverage     71.30%   69.49%   -1.82%     
- Complexity     1275     1326      +51     
============================================
  Files            46       46              
  Lines          3792     3924     +132     
============================================
+ Hits           2704     2727      +23     
- Misses         1088     1197     +109     

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