Do not count attribute overwrites as dropped attributes in AttributesMap

[thswlsqls]

Fixes #8832

Description

• AttributesMap.put() incremented totalAddedValues even when overwriting an existing key. getTotalAttributeCount() exposes that counter and the OTLP marshalers emit total - size as dropped_attributes_count, so setting the same key twice produced dropped_attributes_count=1 below the limit.
• Move the increment into the new-name branch so only inserts and capacity drops are counted.
• Matches the spec (only limit-exceeded attributes may be discarded), the proto comment (0 means nothing dropped), and opentelemetry-go/opentelemetry-python, which do not count overwrites as drops. Log records and recordException events share the class and are corrected too.
• SdkSpanBuilderTest.setAllAttributes_mergesAttributes expectation 8 -> 6: three builder attributes plus five merged (two overlapping names) are six unique names below the limit; the old 8 counted the two overwrites as drops (Add Span#setAttributes method to add Attributes to a Span #2799 did not discuss the number).

Testing done

• Added AttributesMapTest#put_overwriteDoesNotIncrementTotalAddedValues and a getTotalAddedValues() assertion in putSameKeyDifferentType_doesNotConsumeExtraCapacity; both fail without the fix.
• Added SdkSpanTest#overwritingAttribute_doesNotCountAsDropped.
• ./gradlew :sdk:common:check :sdk:trace:check pass; :sdk:logs:test and :exporters:otlp:common:test pass. No apidiff change (internal package).

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Merged · refreshed 2026-09-24 20:22 UTC

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 91.38%. Comparing base (509182e) to head (5a5b9c7).

Additional details and impacted files

@@             Coverage Diff              @@
##               main    #8833      +/-   ##
============================================
+ Coverage     91.34%   91.38%   +0.03%     
- Complexity    10652    10657       +5     
============================================
  Files          1010     1010              
  Lines         28696    28697       +1     
  Branches       3682     3683       +1     
============================================
+ Hits          26212    26224      +12     
+ Misses         1683     1671      -12     
- Partials        801      802       +1     

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