Relative import issue in new dataset boilerplate

/!\ PLEASE INCLUDE THE FULL STACKTRACE AND CODE SNIPPET

Short description
In boilerplate datasets created with tfds new, the default import line in the test file is from . import <name>, which seems to raise an error about relative import.

Environment information

• Operating System: Windows 10.0.19044.1766

• Python version: 3.10.4

• tensorflow-datasets/tfds-nightly version: tensorflow-datasets 4.6.0

• tensorflow/tf-nightly version: tensorflow 2.9.1

• Does the issue still exists with the last tfds-nightly package (pip install --upgrade tfds-nightly) ? Untested, but presumably yes.

Reproduction instructions

tfds new my_ds
python my_ds/my_ds_test.py

Link to logs

Traceback (most recent call last):
  File "C:\Users\Admin\Downloads\my_ds\my_ds_test.py", line 4, in <module>
    from . import my_ds
ImportError: attempted relative import with no known parent package

Expected behavior
Tests should proceed normally.

Additional context
The boilerplate references info.ds_import:
https://github.com/tensorflow/datasets/blob/fdad1d9e8f1cb34389a336132b2f842cbc7aca57/tensorflow_datasets/scripts/cli/new.py#L207
which curiously defaults to . by design:
https://github.com/tensorflow/datasets/blob/fdad1d9e8f1cb34389a336132b2f842cbc7aca57/tensorflow_datasets/scripts/cli/new.py#L63-L67

In this case, changing the line to just import <name> works.

Start in tensorflow_datasets/scripts/cli/new.py, especially the ds_import default and the template generation around the referenced lines. Reproduce the issue with tfds new my_ds followed by python my_ds/my_ds_test.py, then verify the generated test runs normally with the corrected import behavior.