aws-stepfunctions-tasks: Provide task definition as JSONata/JSONPath in .sync EcsRunTask

### Describe the feature

The ability to provide the task definition ARN as a JSONata/JSONPath in `aws_stepfunctions_tasks.EcsRunTask` with the `.sync` integration pattern.

### Use Case

Our team has a requirement to run a ECS RunTask sfn task with the `.sync` integration pattern by using an ECS task definition generated by a subsequent ECS RegisterTaskDefinition sfn task. The most practical way to reference the newly created task definition ARN in the RunTask sfn task is via a JSONata/JSONPath expression. Currently the `aws_stepfunctions_tasks.EcsRunTask` only accepts a `aws_ecs.TaskDefinition`. The `aws_stepfunctions_tasks.CallAwsService` cannot be used a work around since it does not allow the `integrationPattern` to be set to `aws_stepfunctions.IntegrationPattern.RUN_JOB`.

### Proposed Solution

This feature may be introduced as a new string attribute within `aws_stepfunctions_tasks.EcsRunTaskProps`, `taskDefinitionArn`, where either the task definition ARN or a JSONata/JSONPath which evaluates to the task definition ARN may be provided. CDK users must then provide either a `taskDefinition` or `taskDefinitionArn` but not both.

### Other Information

The `aws_cdk.aws_stepfunctions.CustomState` resource can be used as a work around by setting the state `Resource` to `"arn:aws:states:::ecs:runTask.sync"`.

### Acknowledgements

- [x] I may be able to implement this feature request
- [ ] This feature might incur a breaking change

### AWS CDK Library version (aws-cdk-lib)

2.212.0

### AWS CDK CLI version

2.1025.0

### Environment details (OS name and version, etc.)

macOs Sonoma Version 14.6.1

The entry point is aws_stepfunctions_tasks.EcsRunTask and its EcsRunTaskProps; compare the existing taskDefinition path with the CustomState workaround using arn:aws:states:::ecs:runTask.sync. Verify that either taskDefinition or taskDefinitionArn accepts a literal ARN or JSONata/JSONPath, rejects both or neither, and preserves the .sync integration pattern.

Written by the indexing model from the issue text.