Fix warning message typo for environment variable for unrecognized temporality preference (#4790)

Author: emdneto

exporter/opentelemetry-exporter-otlp-proto-common/src/opentelemetry/exporter/otlp/proto/common/_internal/metrics_encoder/__init__.py

@@ -115,7 +115,7 @@ def _get_temporality(
                 "CUMULATIVE"
             ):
                 _logger.warning(
-                    "Unrecognized OTEL_EXPORTER_METRICS_TEMPORALITY_PREFERENCE"
+                    "Unrecognized OTEL_EXPORTER_OTLP_METRICS_TEMPORALITY_PREFERENCE"
                     " value found: "
                     "%s, "
                     "using CUMULATIVE",