### 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)

"labels": self.labels,
            "schema": {"fields": schema_fields},
            "externalDataConfiguration": {
                "source_uris": source_uris,
                "source_format": self.source_format,
                "maxBadRecords": self.max_bad_records,
                "autodetect": self.autodetect,
                "compression": self.compression,
                "csvOptions": {
                    "fieldDelimiter": self.field_delimiter,
                    "skipLeadingRows": self.skip_leading_rows,
                    "quote": self.quote_character,
                    "allowQuotedNewlines": self.allow_quoted_newlines,
                    "allowJaggedRows": self.allow_jagged_rows,
                },
            },
            "location": self.location,
            "encryptionConfiguration": self.encryption_configuration,
        }
        table = bq_hook.create_empty_table(
            table_resource=table_resource,
        )
        BigQueryTableLink.persist(
            context=context,
            task_instance=self,
            dataset_id=table.to_api_repr()["tableReference"]["datasetId"],
            project_id=table.to_api_repr()["tableReference"]["projectId"],
            table_id=table.to_api_repr()["tableReference"]["tableId"],
        )
class BigQueryDeleteDatasetOperator(GoogleCloudBaseOperator):