feat(logs): add metric methods for log group IncomingLogEvents and In…

…comingBytes (#31535)

### Issue

Closes #30034

### Reason for this change
- Create alarms on log ingestion to ensure it is working

### Description of changes

- Add metric methods for log group IncomingLogEvents and IncomingBytes, similar to existing metric methods like metricInvocations on Lambda functions.

### Description of how you validated changes
- validated with new unit tests and a new integration test

### Checklist
- [ ] My code adheres to the [CONTRIBUTING GUIDE](https://github.com/aws/aws-cdk/blob/main/CONTRIBUTING.md) and [DESIGN GUIDELINES](https://github.com/aws/aws-cdk/blob/main/docs/DESIGN_GUIDELINES.md)

----

*By submitting this pull request, I confirm that my contribution is made under the terms of the Apache-2.0 license*

packages/@aws-cdk-testing/framework-integ/test/aws-logs/test/integ.log-group-metrics.js.snapshot/aws-cdk-log-group-metrics.template.json

@@ -0,0 +1,71 @@
+{
+ "Resources": {
+  "MyLogGroup5C0DAD85": {
+   "Type": "AWS::Logs::LogGroup",
+   "Properties": {
+    "LogGroupName": "my-log-group",
+    "RetentionInDays": 731
+   },
+   "UpdateReplacePolicy": "Delete",
+   "DeletionPolicy": "Delete"
+  },
+  "IncomingBytesPerInstanceAlarmFA8EEFDB": {
+   "Type": "AWS::CloudWatch::Alarm",
+   "Properties": {
+    "ComparisonOperator": "GreaterThanOrEqualToThreshold",
+    "EvaluationPeriods": 1,
+    "MetricName": "IncomingBytes",
+    "Namespace": "AWS/Logs",
+    "Period": 300,
+    "Statistic": "Sum",
+    "Threshold": 1
+   }
+  },
+  "IncomingEventsPerInstanceAlarmA9670D55": {
+   "Type": "AWS::CloudWatch::Alarm",
+   "Properties": {
+    "ComparisonOperator": "GreaterThanOrEqualToThreshold",
+    "EvaluationPeriods": 1,
+    "MetricName": "IncomingLogs",
+    "Namespace": "AWS/Logs",
+    "Period": 300,
+    "Statistic": "Sum",
+    "Threshold": 1
+   }
+  }
+ },
+ "Parameters": {
+  "BootstrapVersion": {
+   "Type": "AWS::SSM::Parameter::Value<String>",
+   "Default": "/cdk-bootstrap/hnb659fds/version",
+   "Description": "Version of the CDK Bootstrap resources in this environment, automatically retrieved from SSM Parameter Store. [cdk:skip]"
+  }
+ },
+ "Rules": {
+  "CheckBootstrapVersion": {
+   "Assertions": [
+    {
+     "Assert": {
+      "Fn::Not": [
+       {
+        "Fn::Contains": [
+         [
+          "1",
+          "2",
+          "3",
+          "4",
+          "5"
+         ],
+         {
+          "Ref": "BootstrapVersion"
+         }
+        ]
+       }
+      ]
+     },
+     "AssertDescription": "CDK bootstrap stack version 6 required. Please run 'cdk bootstrap' with a recent version of the CDK CLI."
+    }
+   ]
+  }
+ }
+}