fix: don't call batch() if batch == False

[MikeWalrus]

Description

Currently, creating a CKKSTensor from a PyTorch scalar throws an exception even with batch=False.

import torch
import tenseal as ts

ctx = ts.context(
    ts.SCHEME_TYPE.CKKS, 8192, coeff_mod_bit_sizes=[60, 40, 40, 60]
)
ctx.global_scale = 2**10

ts.CKKSTensor(ctx, torch.tensor(3), batch=False)

Traceback (most recent call last):
  File "a.py", line 9, in <module>
    ts.CKKSTensor(ctx, torch.tensor(3), batch=False)
  File "...python3.10/site-packages/tenseal/tensors/ckkstensor.py", line 44, in __init__
    self.data = ts._ts_cpp.CKKSTensor(context.data, tensor.data, batch)
ValueError: invalid dimension for batching

This pr fixes it by not calling TensorStorage::batch if batch==false.

Affected Dependencies

None.

How has this been tested?

• Describe the tests that you ran to verify your changes.
• Provide instructions so we can reproduce.
• List any relevant details for your test configuration.

Checklist

• I have followed the Contribution Guidelines and Code of Conduct
• I have commented my code following the OpenMined Styleguide
• I have labeled this PR with the relevant Type labels
• My changes are covered by tests

[bcebere]

Thank you for the contribution!

Can you please add a test that was failing before, and it is working with your fix? Thanks!

[MikeWalrus]

Haven't got the time to look at the testing code yet. I'll try to add the test someday.

[bcebere]

Haven't got the time to look at the testing code yet. I'll try to add the test someday.

Thanks! A Python test is enough to cover the fix, and to justify it in the future.

[jiejiejie5335]

hello, i wonder is there any other plain_modulus that can be used in BFV? I find only 1032191 and 786433 can worked other wise will cause the error: ValueError: encryption parameters are not valid for batching