Missing Promise functions on BatchTransaction

[pequalsnp]

Environment details

• OS: OSX
• Node.js version: v18.16.0
• npm version: 9.5.1
• @google-cloud/spanner version: 6.12.0

Steps to reproduce

1. Use Typescript
2. Attempt to use batch transactions as shown in samples/batch.js

    const query = {
      sql: `
        select
          *
        from
          ${POST_TABLE_NAME}
      `,
    };

    const [transaction] = await this.database.createBatchTransaction();
    const partitions = transaction.createQueryPartitions(query);

3. Get tsc error:

    domains/archive/post-service/src/post-service-spanner.repository.ts:274:11 - error TS2488: Type 'void' must have a '[Symbol.iterator]()' method that returns an iterator.

    274     const [partitions] = await transaction.createQueryPartitions(query);
                  ~~~~~~~~~~~~
    domains/archive/post-service/src/post-service-spanner.repository.ts:274:44 - error TS2554: Expected 2 arguments, but got 1.

    274     const [partitions] = await transaction.createQueryPartitions(query);
                                                   ~~~~~~~~~~~~~~~~~~~~~~~~~~~~

      node_modules/@google-cloud/spanner/build/src/batch-transaction.d.ts:111:39
        111     createQueryPartitions(query: any, callback: any): void;
                                                  ~~~~~~~~~~~~~
        An argument for 'callback' was not provided.

The problem appears to be that your use of promisifyAll doesn't cause the appropriate method types to be included in the .d.ts file.

[rahul2393]

@surbhigarg92 please help triage this.