### 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)

"""Return operator extra links"""
        if isinstance(self.sql, str):
            return (BigQueryConsoleLink(),)
        return (BigQueryConsoleIndexableLink(i) for i, _ in enumerate(self.sql))
    def __init__(
        self,
        *,
        sql: str | Iterable[str],
        destination_dataset_table: str | None = None,
        write_disposition: str = "WRITE_EMPTY",
        allow_large_results: bool = False,
        flatten_results: bool | None = None,
        gcp_conn_id: str = "google_cloud_default",
        udf_config: list | None = None,
        use_legacy_sql: bool = True,
        maximum_billing_tier: int | None = None,
        maximum_bytes_billed: float | None = None,
        create_disposition: str = "CREATE_IF_NEEDED",
        schema_update_options: list | tuple | set | None = None,
        query_params: list | None = None,
        labels: dict | None = None,
        priority: str = "INTERACTIVE",
        time_partitioning: dict | None = None,
        api_resource_configs: dict | None = None,
        cluster_fields: list[str] | None = None,
        location: str | None = None,
        encryption_configuration: dict | None = None,
        impersonation_chain: str | Sequence[str] | None = None,
        **kwargs,