### Apache Airflow version

main (development)

### What happened

1. When not providing `project_id` to `BigQueryGetDataOperator` in deferrable mode (`project_id=None`), the query generated by `generate_query` method is bugged, i.e.,: 

````sql
from `None.DATASET.TABLE_ID` limit ...
````

2. `as_dict` param does not work `BigQueryGetDataOperator`.

### What you think should happen instead

1. When `project_id` is `None` - it should be removed from the query along with the trailing dot, i.e.,:

````sql
from `DATASET.TABLE_ID` limit ...
````

2. `as_dict` should be added to the serialization method of `BigQueryGetDataTrigger`.

### How to reproduce

1. Create a DAG file with `BigQueryGetDataOperator` defined as follows:
```python
BigQueryGetDataOperator(
        task_id="bq_get_data_op",
        # project_id="PROJECT_ID",  <-- Not provided
        dataset_id="DATASET",
        table_id="TABLE",
        use_legacy_sql=False,
        deferrable=True
    )
````

2. 1. Create a DAG file with `BigQueryGetDataOperator` defined as follows:
```python
BigQueryGetDataOperator(
        task_id="bq_get_data_op",
        project_id="PROJECT_ID",
        dataset_id="DATASET",
        table_id="TABLE",
        use_legacy_sql=False,
        deferrable=True,
        as_dict=True
    )
````

### Operating System

Debian

### Versions of Apache Airflow Providers

_No response_

### Deployment

Official Apache Airflow Helm Chart

### Deployment details

_No response_

### Anything else

The `generate_query` method is not unit tested (which would have prevented it in the first place) - will be better to add one.

### Are you willing to submit PR?

- [X] Yes I am willing to submit a PR!

### Code of Conduct

- [X] I agree to follow this project's [Code of Conduct](https://github.com/apache/airflow/blob/main/CODE_OF_CONDUCT.md)

self.log.info("Dataset id: %s Project id: %s", self.dataset_id, self.project_id)
        bq_hook = BigQueryHook(
            gcp_conn_id=self.gcp_conn_id,
            impersonation_chain=self.impersonation_chain,
        )
        bq_hook.delete_dataset(
            project_id=self.project_id, dataset_id=self.dataset_id, delete_contents=self.delete_contents
        )
class BigQueryCreateEmptyDatasetOperator(GoogleCloudBaseOperator):
    """
    This operator is used to create new dataset for your Project in BigQuery.
    https://cloud.google.com/bigquery/docs/reference/rest/v2/datasets#resource
    .. seealso::
        For more information on how to use this operator, take a look at the guide:
        :ref:`howto/operator:BigQueryCreateEmptyDatasetOperator`
    :param project_id: The name of the project where we want to create the dataset.
    :param dataset_id: The id of dataset. Don't need to provide, if datasetId in dataset_reference.
    :param location: The geographic location where the dataset should reside.
    :param dataset_reference: Dataset reference that could be provided with request body.
        More info:
        https://cloud.google.com/bigquery/docs/reference/rest/v2/datasets#resource
    :param gcp_conn_id: (Optional) The connection ID used to connect to Google Cloud.
    :param impersonation_chain: Optional service account to impersonate using short-term