sdk: set correct span limit in builder

[djc]

#2303 refactored the TracerProvider builder to deprecate the Config API. I like the API changes this resulted in, but the Builder::max_events_per_span() method sets the incorrect span_limits.max_attributes_per_span field.

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 1 line in your changes missing coverage. Please review.

Project coverage is 79.3%. Comparing base (902baa9) to head (7345df0).
Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
opentelemetry-sdk/src/trace/provider.rs	0.0%	1 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##            main   #2405     +/-   ##
=======================================
- Coverage   79.3%   79.3%   -0.1%     
=======================================
  Files        123     123             
  Lines      21566   21566             
=======================================
- Hits       17112   17108      -4     
- Misses      4454    4458      +4     

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

[cijothomas]

Thanks!