[chore] [processor/batch] docs: stop recommending Batch processor

[andrzej-stencel]

Removes the sentence in Batch processor docs recommending using the component on every collector.

This implements one of the points proposed in:

• [processor/batch] Batch processor drops data that failed to be sent #12443

• Stop recommending to configure the Batch processor on every collector pipeline.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 91.55%. Comparing base (35668a1) to head (746b9e3).
Report is 4 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #13191      +/-   ##
==========================================
- Coverage   91.57%   91.55%   -0.03%     
==========================================
  Files         522      522              
  Lines       29089    29089              
==========================================
- Hits        26639    26631       -8     
- Misses       1933     1939       +6     
- Partials      517      519       +2     

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