Remove export timeout configuration for PeriodicReader

[lalitb]

Fixes: towards #2576

Changes

Similar to #2587

Merge requirement checklist

• CONTRIBUTING guidelines followed
• Unit tests added/updated (if applicable)
• Appropriate CHANGELOG.md files updated for non-trivial, user-facing changes
• Changes in public API reviewed (if applicable)

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 79.0%. Comparing base (15b5fa4) to head (bdffeb8).
Report is 1 commits behind head on main.

Additional details and impacted files

@@          Coverage Diff          @@
##            main   #2598   +/-   ##
=====================================
  Coverage   79.0%   79.0%           
=====================================
  Files        119     119           
  Lines      22550   22531   -19     
=====================================
- Hits       17830   17819   -11     
+ Misses      4720    4712    -8     

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[cijothomas]

LGTM. Will include this in migration guide I am preparing.
We need to mention the fact that rogue observable instruments can stall entire sdk in some docs.