### 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_
pass
SERVICE_PORTS = parse_service_ports()
def populate_config_env_var_names():
    global CONFIG_ENV_VARS
    for key, value in DEFAULT_SERVICE_PORTS.items():
        clean_key = key.upper().replace("-", "_")
        CONFIG_ENV_VARS += [
            clean_key + "_BACKEND",
            clean_key + "_PORT_EXTERNAL",
            "PROVIDER_OVERRIDE_" + clean_key,
        ]
    
    CONFIG_ENV_VARS += [
        "LOCALSTACK_" + v for v in CONFIG_ENV_VARS if not v.startswith("LOCALSTACK_")
    ]
    CONFIG_ENV_VARS = list(set(CONFIG_ENV_VARS))
populate_config_env_var_names()
def service_port(service_key: str, external: bool = False) -> int: