Support max batch size for metrics

[dyladan]

During #2220 @arminru discovered that the max batch size was only applied to spans. This applies the same logic to metrics.

[codecov]

Codecov Report

Merging #2422 (11bc205) into main (bd70c80) will decrease coverage by 0.05%.
The diff coverage is 76.74%.

@@            Coverage Diff             @@
##             main    #2422      +/-   ##
==========================================
- Coverage   91.93%   91.87%   -0.06%     
==========================================
  Files         269      270       +1     
  Lines       15278    15326      +48     
==========================================
+ Hits        14046    14081      +35     
- Misses        854      866      +12     
- Partials      378      379       +1     

Impacted Files	Coverage Δ
processor/batchprocessor/batch_processor.go	90.08% <0.00%> (-6.38%)	⬇️
processor/batchprocessor/splitmetrics.go	94.28% <94.28%> (ø)
exporter/exporterhelper/metricshelper.go	94.59% <0.00%> (-5.41%)	⬇️
internal/data/bytesid.go	76.92% <0.00%> (-4.03%)	⬇️
exporter/otlpexporter/otlp.go	71.79% <0.00%> (-2.57%)	⬇️
internal/data/traceid.go	92.30% <0.00%> (+7.69%)	⬆️

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