[AWS::RDS::DBParameterGroup] - [Coverage] - `postgres13` missing Drift Detection support for `Parameters`

### Name of the resource

AWS::RDS::DBParameterGroup

### Resource name

_No response_

### Description

For some unknown reason CloudFormation Drift Detection is unable to verify the integrity of `Parameters` in a `postgres13` `AWS::RDS::DBParameterGroup`. Example:

```yaml
AWSTemplateFormatVersion: 2010-09-09
Description: Example

Resources:
DBParameterGroup:
Type: AWS::RDS::DBParameterGroup
Properties:
Description: "Parameter Group"
Family: postgres13
Parameters:
shared_preload_libraries: pg_stat_statements
```

this will cause a false-positive drift:

Property | Change | Expected value | Current value
-- | -- | -- | --
Parameters | REMOVE | {} | -

### Other Details

_No response_

Start with the supplied AWS::RDS::DBParameterGroup template using Family postgres13 and the Parameters value shared_preload_libraries: pg_stat_statements, then reproduce the CloudFormation drift result. Done means drift detection recognizes Parameters correctly instead of reporting a false REMOVE change with an expected value of {}.

Written by the indexing model from the issue text.