### 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)

job: BigQueryJob | UnknownJob = self._submit_job(hook, job_id)
        except Conflict:
            
            job = hook.get_job(
                project_id=self.project_id,
                location=self.location,
                job_id=job_id,
            )
            if job.state in self.reattach_states:
                
                job._begin()
                self._handle_job_error(job)
            else:
                
                raise AirflowException(
                    f"Job with id: {job_id} already exists and is in {job.state} state. If you "
                    f"want to force rerun it consider setting `force_rerun=True`."
                    f"Or, if you want to reattach in this scenario add {job.state} to `reattach_states`"
                )
        job_types = {
            LoadJob._JOB_TYPE: ["sourceTable", "destinationTable"],
            CopyJob._JOB_TYPE: ["sourceTable", "destinationTable"],
            ExtractJob._JOB_TYPE: ["sourceTable"],
            QueryJob._JOB_TYPE: ["destinationTable"],
        }
        if self.project_id:
            for job_type, tables_prop in job_types.items():
                job_configuration = job.to_api_repr()["configuration"]
                if job_type in job_configuration:
                    for table_prop in tables_prop: