feat(ec2): support the new ServiceRegion property for AWS::EC2::VPCEndpoint (#35025)

### Issue # (if applicable)

Closes #32785 

### Reason for this change

Supporting the new L1 property in the L2 construct. `AWS::EC2::VPCEndpointService` support was added in #33959, so this should complete support for cross-region vpc private links.

### Description of changes

Added a new L2 prop - `serviceRegion` - which is of type `string`. It gets passed to the L1 `ServiceRegion` property when present.

### Describe any new or updated permissions being added

None

### Description of how you validated changes

Added unit tests

### Checklist
- [X] 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*

Author: richarddotcodes

packages/@aws-cdk-testing/framework-integ/test/aws-ec2/test/integ.vpc-endpoint.lit.js.snapshot/aws-cdk-ec2-vpc-endpoint.assets.json

@@ -774,6 +774,90 @@
      "Ref": "MyVpcF9F0CA6F"
     }
    }
+  },
+  "MyVpcCrossRegionEndpointSecurityGroup371BDCEC": {
+   "Type": "AWS::EC2::SecurityGroup",
+   "Properties": {
+    "GroupDescription": "aws-cdk-ec2-vpc-endpoint/MyVpc/CrossRegionEndpoint/SecurityGroup",
+    "SecurityGroupEgress": [
+     {
+      "CidrIp": "0.0.0.0/0",
+      "Description": "Allow all outbound traffic by default",
+      "IpProtocol": "-1"
+     }
+    ],
+    "SecurityGroupIngress": [
+     {
+      "CidrIp": {
+       "Fn::GetAtt": [
+        "MyVpcF9F0CA6F",
+        "CidrBlock"
+       ]
+      },
+      "Description": {
+       "Fn::Join": [
+        "",
+        [
+         "from ",
+         {
+          "Fn::GetAtt": [
+           "MyVpcF9F0CA6F",
+           "CidrBlock"
+          ]
+         },
+         ":443"
+        ]
+       ]
+      },
+      "FromPort": 443,
+      "IpProtocol": "tcp",
+      "ToPort": 443
+     }
+    ],
+    "Tags": [
+     {
+      "Key": "Name",
+      "Value": "aws-cdk-ec2-vpc-endpoint/MyVpc"
+     }
+    ],
+    "VpcId": {
+     "Ref": "MyVpcF9F0CA6F"
+    }
+   }
+  },
+  "MyVpcCrossRegionEndpoint9A9ABB87": {
+   "Type": "AWS::EC2::VPCEndpoint",
+   "Properties": {
+    "PrivateDnsEnabled": false,
+    "SecurityGroupIds": [
+     {
+      "Fn::GetAtt": [
+       "MyVpcCrossRegionEndpointSecurityGroup371BDCEC",
+       "GroupId"
+      ]
+     }
+    ],
+    "ServiceName": "com.amazonaws.vpce.us-east-1.vpce-svc-123456",
+    "ServiceRegion": "us-east-1",
+    "SubnetIds": [
+     {
+      "Ref": "MyVpcPrivateSubnet1Subnet5057CF7E"
+     },
+     {
+      "Ref": "MyVpcPrivateSubnet2Subnet0040C983"
+     }
+    ],
+    "Tags": [
+     {
+      "Key": "Name",
+      "Value": "aws-cdk-ec2-vpc-endpoint/MyVpc"
+     }
+    ],
+    "VpcEndpointType": "Interface",
+    "VpcId": {
+     "Ref": "MyVpcF9F0CA6F"
+    }
+   }
   }
  },
  "Parameters": {