[connector/signaltometrics]Fix typo for AdjustedCount in README (#38642)

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#### Description

Fixes a typo in custom OTTL func name.

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Raised in
#38640 (comment)

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Author: lahsivjar

connector/signaltometricsconnector/README.md

@@ -42,7 +42,7 @@ signaltometrics:
     - name: span.count
       description: Count of spans
       sum:
-        value: Int(AbsoluteCount()) # Count of total spans represented by each span
+        value: Int(AdjustedCount()) # Count of total spans represented by each span
   datapoints:
     - name: datapoint.count
       description: Count of datapoints