E tag fix (Azure#37364)

* ETag fix

* Update _constants.py

Author: mrm9084

sdk/appconfiguration/azure-appconfiguration-provider/azure/appconfiguration/provider/_constants.py

@@ -20,8 +20,9 @@
 TELEMETRY_KEY = "telemetry"
 METADATA_KEY = "metadata"
 ETAG_KEY = "ETag"
-FEATURE_FLAG_REFERENCE_KEY = "feature_flag_reference"
-FEATURE_FLAG_ID_KEY = "feature_flag_id"
+
+FEATURE_FLAG_REFERENCE_KEY = "FeatureFlagReference"
+FEATURE_FLAG_ID_KEY = "FeatureFlagId"
 PERCENTAGE_FILTER_NAMES = ["Percentage", "PercentageFilter", "Microsoft.Percentage", "Microsoft.PercentageFilter"]
 TIME_WINDOW_FILTER_NAMES = ["TimeWindow", "TimeWindowFilter", "Microsoft.TimeWindow", "Microsoft.TimeWindowFilter"]
 TARGETING_FILTER_NAMES = ["Targeting", "TargetingFilter", "Microsoft.Targeting", "Microsoft.TargetingFilter"]