fix(ecr): incorrect format for rule pattern (#29243)

Closes #29225. 

----

*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-ecr/test/integ.basic.js.snapshot/aws-ecr-integ-stack.template.json

@@ -22,10 +22,10 @@
    "UpdateReplacePolicy": "Retain",
    "DeletionPolicy": "Retain"
   },
-  "MyUserDC45028B": {
+  "MyIamUser046086A4": {
    "Type": "AWS::IAM::User"
   },
-  "MyUserDefaultPolicy7B897426": {
+  "MyIamUserDefaultPolicy4B9C0A95": {
    "Type": "AWS::IAM::Policy",
    "Properties": {
     "PolicyDocument": {
@@ -58,10 +58,10 @@
      ],
      "Version": "2012-10-17"
     },
-    "PolicyName": "MyUserDefaultPolicy7B897426",
+    "PolicyName": "MyIamUserDefaultPolicy4B9C0A95",
     "Users": [
      {
-      "Ref": "MyUserDC45028B"
+      "Ref": "MyIamUser046086A4"
      }
     ]
    }
@@ -73,6 +73,109 @@
    },
    "UpdateReplacePolicy": "Delete",
    "DeletionPolicy": "Delete"
+  },
+  "RepoOnEvent13B6ADDB": {
+   "Type": "AWS::ECR::Repository",
+   "UpdateReplacePolicy": "Retain",
+   "DeletionPolicy": "Retain"
+  },
+  "RepoOnEventOnEventTargetLambda2934FA99": {
+   "Type": "AWS::Events::Rule",
+   "Properties": {
+    "EventPattern": {
+     "source": [
+      "aws.ecr"
+     ],
+     "detail": {
+      "repository-name": [
+       {
+        "Ref": "RepoOnEvent13B6ADDB"
+       }
+      ]
+     }
+    },
+    "State": "ENABLED",
+    "Targets": [
+     {
+      "Arn": {
+       "Fn::GetAtt": [
+        "LambdaFunctionBF21E41F",
+        "Arn"
+       ]
+      },
+      "Id": "Target0"
+     }
+    ]
+   }
+  },
+  "RepoOnEventOnEventTargetLambdaAllowEventRuleawsecrintegstackLambdaFunctionB6045AA7FBA3AA33": {
+   "Type": "AWS::Lambda::Permission",
+   "Properties": {
+    "Action": "lambda:InvokeFunction",
+    "FunctionName": {
+     "Fn::GetAtt": [
+      "LambdaFunctionBF21E41F",
+      "Arn"
+     ]
+    },
+    "Principal": "events.amazonaws.com",
+    "SourceArn": {
+     "Fn::GetAtt": [
+      "RepoOnEventOnEventTargetLambda2934FA99",
+      "Arn"
+     ]
+    }
+   }
+  },
+  "LambdaFunctionServiceRoleC555A460": {
+   "Type": "AWS::IAM::Role",
+   "Properties": {
+    "AssumeRolePolicyDocument": {
+     "Statement": [
+      {
+       "Action": "sts:AssumeRole",
+       "Effect": "Allow",
+       "Principal": {
+        "Service": "lambda.amazonaws.com"
+       }
+      }
+     ],
+     "Version": "2012-10-17"
+    },
+    "ManagedPolicyArns": [
+     {
+      "Fn::Join": [
+       "",
+       [
+        "arn:",
+        {
+         "Ref": "AWS::Partition"
+        },
+        ":iam::aws:policy/service-role/AWSLambdaBasicExecutionRole"
+       ]
+      ]
+     }
+    ]
+   }
+  },
+  "LambdaFunctionBF21E41F": {
+   "Type": "AWS::Lambda::Function",
+   "Properties": {
+    "Code": {
+     "ZipFile": "# dummy func"
+    },
+    "Handler": "index.handler",
+    "Role": {
+     "Fn::GetAtt": [
+      "LambdaFunctionServiceRoleC555A460",
+      "Arn"
+     ]
+    },
+    "Runtime": "python3.12"
+   },
+   "DependsOn": [
+    "LambdaFunctionServiceRoleC555A460"
+   ]
   }
  },
  "Outputs": {