[exporter/awsemfexporter] Propagate RetainInitialValueOfDeltaMetric to translateOTelToGroupedMetric (#24051)

**Description:**

The config option `retain_initial_value_of_delta_metric` does not seem
to be used in `translateOTelToGroupedMetric`, which prevents the initial
value of a basic counter from being published during a Lambda cold boot.

Please see the minimum project required to replicate the issue
[here](https://github.com/jameshi16/delta-initial-value-minimum-project).

**Link to tracking Issue:** The main issue related to this PR can be
found
[here](aws-observability/aws-otel-lambda#634).

It seems like I had a predecessor fixing this issue (see #17988), but
his changes does not work for my use case.

**Testing:** An additional test ensures that if
`retain_initial_value_of_delta_metric` is set, it will be propagated to
the `cWMetricMetadata`.

**Documentation:** None

Author: jameshi16

.chloggen/awsemfexporter-publish-initial-metrics.yaml

@@ -0,0 +1,20 @@
+# Use this changelog template to create an entry for release notes.
+# If your change doesn't affect end users, such as a test fix or a tooling change,
+# you should instead start your pull request title with [chore] or use the "Skip Changelog" label.
+
+# One of 'breaking', 'deprecation', 'new_component', 'enhancement', 'bug_fix'
+change_type: bug_fix
+
+# The name of the component, or a single word describing the area of concern, (e.g. filelogreceiver)
+component: awsemfexporter
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Add retain_initial_value_of_delta_metric to translateOTelToGroupedMetric, allowing the initial set of metrics to be published
+
+# Mandatory: One or more tracking issues related to the change. You can use the PR number here if no issue exists.
+issues: [24051]
+
+# (Optional) One or more lines of additional information to render under the primary note.
+# These lines will be padded with 2 spaces and then inserted directly into the document.
+# Use pipe (|) for multiline entries.
+subtext:

exporter/awsemfexporter/metric_translator.go

@@ -117,6 +117,7 @@ func (mt metricTranslator) translateOTelToGroupedMetric(rm pmetric.ResourceMetri
 	var instrumentationScopeName string
 	cWNamespace := getNamespace(rm, config.Namespace)
 	logGroup, logStream, patternReplaceSucceeded := getLogInfo(rm, cWNamespace, config)
+	deltaInitialValue := config.RetainInitialValueOfDeltaMetric
 
 	ilms := rm.ScopeMetrics()
 	var metricReceiver string
@@ -134,11 +135,12 @@ func (mt metricTranslator) translateOTelToGroupedMetric(rm pmetric.ResourceMetri
 			metric := metrics.At(k)
 			metadata := cWMetricMetadata{
 				groupedMetricMetadata: groupedMetricMetadata{
-					namespace:      cWNamespace,
-					timestampMs:    timestamp,
-					logGroup:       logGroup,
-					logStream:      logStream,
-					metricDataType: metric.Type(),
+					namespace:                  cWNamespace,
+					timestampMs:                timestamp,
+					logGroup:                   logGroup,
+					logStream:                  logStream,
+					metricDataType:             metric.Type(),
+					retainInitialValueForDelta: deltaInitialValue,
 				},
 				instrumentationScopeName: instrumentationScopeName,
 				receiver:                 metricReceiver,

exporter/awsemfexporter/metric_translator_test.go

@@ -2343,6 +2343,36 @@ func TestTranslateOtToGroupedMetricForLogGroupAndStream(t *testing.T) {
 	}
 }
 
+func TestTranslateOtToGroupedMetricForInitialDeltaValue(t *testing.T) {
+	for _, test := range logGroupStreamTestCases {
+		t.Run(test.name, func(t *testing.T) {
+			config := &Config{
+				Namespace:                       "",
+				LogGroupName:                    test.inLogGroupName,
+				LogStreamName:                   test.inLogStreamName,
+				DimensionRollupOption:           zeroAndSingleDimensionRollup,
+				logger:                          zap.NewNop(),
+				RetainInitialValueOfDeltaMetric: true,
+			}
+
+			translator := newMetricTranslator(*config)
+
+			groupedMetrics := make(map[interface{}]*groupedMetric)
+
+			rm := test.inputMetrics.ResourceMetrics().At(0)
+			err := translator.translateOTelToGroupedMetric(rm, groupedMetrics, config)
+			assert.Nil(t, err)
+
+			assert.NotNil(t, groupedMetrics)
+			assert.Equal(t, 1, len(groupedMetrics))
+
+			for _, actual := range groupedMetrics {
+				assert.True(t, actual.metadata.retainInitialValueForDelta)
+			}
+		})
+	}
+}
+
 func generateTestMetrics(tm testMetric) pmetric.Metrics {
 	md := pmetric.NewMetrics()
 	now := time.Now()