[train_dreambooth_lora.py] Set LANCZOS as default interpolation mode for resizing

[merterbak]

What does this PR do?

It makes LANCZOS the default interpolation mode for the image resizing. It fixes #11390.

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Who can review?

@asomoza

[HuggingFaceDocBuilderDev]

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[asomoza]

thanks @merterbak, for contributing in diffusers you have to format the code, can you run these two commands on the console:

make style
make quality

If for some reason you can't run them, I can run a bot that does this for you, but it's always better to run it yourself, specially for larger contributions of code with multiple reviews.

[merterbak]

Ok, thank you for valuable advice.

[asomoza]

thanks a lot!

[asomoza]

failing test are not related to this PR