### Is there an existing issue for this?

- [X] I have searched the existing issues

### Current Behavior

The documentation states that when setting DYNAMODB_SHARE_DB=1 DynamodDB will use a single database for each credential and region. This doesn't work when LocalStack is started from CLI. For example:

`DYNAMODB_SHARE_DB=1 localstack start -d`

In Docker logs you can find:
INFO:localstack.services.dynamodb.server: SharedDb:     false

At least it seems that the environment variable is missing from CONFIG_ENV_VARS which is used for passing the environment variables to container.

Tried the following fix and at least after brief testing it solves the issue:
https://github.com/jvuori/localstack/commit/6bb4a3c68c8675b9548e0f5eb8028397d9ee5a47
Feel free to pull if the fix is appropriate. (Sorry, no unit test...)

### Expected Behavior

`DYNAMODB_SHARE_DB=1 localstack start -d`
should start DynamoDB with:

INFO:localstack.services.dynamodb.server: SharedDb:     true

### How are you starting LocalStack?

With the `localstack` script

### Steps To Reproduce

#### How are you starting localstack (e.g., `bin/localstack` command, arguments, or `docker-compose.yml`)

DYNAMODB_SHARE_DB=1 localstack start -d


### Environment

```markdown
- OS: Windows + WSL2 + Docker CE running inside WSL2
- LocalStack: 0.14.1
```


### Anything else?

_No response_
"""Parses the environment variable $SERVICES with a comma-separated list of services
    and (optional) ports they should run on: 'service1:port1,service2,service3:port3'"""
    service_ports = os.environ.get("SERVICES", "").strip()
    if not service_ports:
        return DEFAULT_SERVICE_PORTS
    result = {}
    for service_port in re.split(r"\s*,\s*", service_ports):
        parts = re.split(r"[:=]", service_port)
        service = parts[0]
        key_upper = service.upper().replace("-", "_")
        port_env_name = "%s_PORT" % key_upper
        
        port_number = DEFAULT_SERVICE_PORTS.get(service)
        
        if os.environ.get(port_env_name):
            port_number = os.environ.get(port_env_name)
        
        if len(parts) > 1:
            port_number = int(parts[-1])
        
        try:
            port_number = int(port_number)
        except Exception:
            port_number = 0
        result[service] = port_number
    return result
def populate_configs(service_ports=None):