automatically validate datasets configs in statgpt

### StatGPT Backend version

latest (0.3.0)

### What is the problem this feature will solve?

- we want to check if dataset configs are valid: correspond to pydantic schema and contain exactly the same dimensions as DSD
- we want to run this validation automatically. for example when:
- updating dataset configs
- starting statgpt admin app
- pushing changes to dataset configs to git

### What is the proposed feature or solution?

- decide **when** to run such validation
- call `statgpt.common.data.base.datasource.DataSourceHandler.validate_dataset_config()` method (it parses incoming `dict` to config instance and validates it against DSD) in any place we decide to add such check

### What alternatives have you considered?

_No response_