feat: extract identifier label for login from default identity schema

[zepatrik]

closes #3041

[codecov]

Codecov Report

Attention: 22 lines in your changes are missing coverage. Please review.

Comparison is base (c25ddff) 78.40% compared to head (8b33a1e) 78.37%.

Files	Patch %	Lines
...lfservice/flow/login/extension_identifier_label.go	86.66%	2 Missing and 2 partials ⚠️
selfservice/strategy/code/strategy.go	42.85%	2 Missing and 2 partials ⚠️
selfservice/strategy/code/strategy_login.go	42.85%	2 Missing and 2 partials ⚠️
selfservice/strategy/password/login.go	42.85%	2 Missing and 2 partials ⚠️
selfservice/strategy/webauthn/login.go	42.85%	2 Missing and 2 partials ⚠️
schema/extension.go	87.50%	1 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #3645      +/-   ##
==========================================
- Coverage   78.40%   78.37%   -0.04%     
==========================================
  Files         344      345       +1     
  Lines       23494    23558      +64     
==========================================
+ Hits        18421    18463      +42     
- Misses       3688     3699      +11     
- Partials     1385     1396      +11     

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