chore(region-info): add appmesh ecr accounts for ap-southeast-3 (#21932)

Add ECR account of `ap-southeast-3` for AWS App Mesh.

`ap-southeast-3` is an opt-in region, so we have to manually add the new ECR account.

----

### All Submissions:

* [Y] Have you followed the guidelines in our [Contributing guide?](https://github.com/aws/aws-cdk/blob/main/CONTRIBUTING.md)

### Adding new Unconventional Dependencies:

* [Y] This PR adds new unconventional dependencies following the process described [here](https://github.com/aws/aws-cdk/blob/main/CONTRIBUTING.md/#adding-new-unconventional-dependencies)

### New Features

* [N] Have you added the new feature to an [integration test](https://github.com/aws/aws-cdk/blob/main/INTEGRATION_TESTS.md)?
	* [ ] Did you use `yarn integ` to deploy the infrastructure and generate the snapshot (i.e. `yarn integ` without `--dry-run`)?

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

.gitallowed

@@ -25,6 +25,7 @@ account: '422531588944'
 account: '924023996002'
 account: '919366029133' #cn-north-1
 account: '919830735681' #cn-northwest-1
+account: '909464085924' #ap-southeast-3
 
 # The account IDs of password rotation applications of Serverless Application Repository
 # https://docs.aws.amazon.com/secretsmanager/latest/userguide/enable-rotation-rds.html

packages/@aws-cdk/region-info/build-tools/fact-tables.ts

@@ -171,6 +171,7 @@ export const APPMESH_ECR_ACCOUNTS: { [region: string]: string } = {
   'ap-south-1': '840364872350',
   'ap-southeast-1': '840364872350',
   'ap-southeast-2': '840364872350',
+  'ap-southeast-3': '909464085924',
   'ca-central-1': '840364872350',
   'cn-north-1': '919366029133',
   'cn-northwest-1': '919830735681',