### 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)

selected_fields=self.selected_fields,
                location=self.location,
                project_id=self.project_id,
            )
            if isinstance(rows, RowIterator):
                raise TypeError(
                    "BigQueryHook.list_rows() returns iterator when return_iterator is False (default)"
                )
            self.log.info("Total extracted rows: %s", len(rows))
            if self.as_dict:
                table_data = [{k: v for k, v in row.items()} for row in rows]
            else:
                table_data = [row.values() for row in rows]
            return table_data
        job = self._submit_job(hook, job_id="")
        context["ti"].xcom_push(key="job_id", value=job.job_id)
        self.defer(
            timeout=self.execution_timeout,
            trigger=BigQueryGetDataTrigger(
                conn_id=self.gcp_conn_id,
                job_id=job.job_id,
                dataset_id=self.dataset_id,
                table_id=self.table_id,
                project_id=hook.project_id,
                poll_interval=self.poll_interval,
                as_dict=self.as_dict,
            ),
            method_name="execute_complete",
        )
    def execute_complete(self, context: Context, event: dict[str, Any]) -> Any: