Minor fixes to PeriodicReader and examples

[cijothomas]

Cleanup unwanted duplicate attributes from internal logs
Example - re-order initialization to ensure Logs are initialized first, so we can see internal logs from metric/trace provider initialization.
Remove unwanted feature flags.

[Copilot]

Copilot reviewed 5 out of 6 changed files in this pull request and generated no suggestions.

Files not reviewed (1)

• opentelemetry-otlp/examples/basic-otlp-http/Cargo.toml: Evaluated as low risk

[codecov]

Codecov Report

Attention: Patch coverage is 63.63636% with 4 lines in your changes missing coverage. Please review.

Project coverage is 79.3%. Comparing base (238a8f2) to head (4de12ee).
Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
opentelemetry-sdk/src/metrics/periodic_reader.rs	63.6%	4 Missing ⚠️

Additional details and impacted files

@@          Coverage Diff          @@
##            main   #2409   +/-   ##
=====================================
  Coverage   79.2%   79.3%           
=====================================
  Files        123     122    -1     
  Lines      21527   21511   -16     
=====================================
- Hits       17069   17060    -9     
+ Misses      4458    4451    -7     

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