fix: README_flux2.md fsdp config error

[Thundermean-sky]

What does this PR do?

Fix incorrect FSDP configuration examples in the examples/dreambooth/README_flux2.md.

While training, I encountered two issues with the config examples in the README:

1. The value of fsdp_auto_wrap_policy was incorrect, which caused training to fail.
2. There was an extra space between the two class names in fsdp_transformer_layer_cls_to_wrap (Flux2TransformerBlock, Flux2SingleTransformerBlock). Removing the space resolved the error.

After correcting both parameters, the training runs successfully.

This PR updates the README with the corrected FSDP configuration examples.

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[Thundermean-sky]

Note:
Regarding the space between Flux2TransformerBlock and Flux2SingleTransformerBlock in fsdp_transformer_layer_cls_to_wrap: I removed the space because it caused an error in my environment. I'm not sure if this is a general issue or something specific to my setup. Feedback is welcome.

[github-actions]

Hi @Thundermean-sky, thanks for the PR! It does not appear to link an issue it fixes. If this PR addresses an existing issue, please add a closing keyword (e.g. Fixes #1234) to the PR description so the issue is linked. See the contribution guide for more details. If this PR intentionally does not fix a tracked issue, a maintainer can add the no-issue-needed label to silence this reminder.

Please note that PRs without a linked issue are likely to be automatically closed 10 days after this notice.

Once the PR links an issue (or gets the no-issue-needed label), you can ignore this message — it stays here as a comment, but it no longer applies.

[Thundermean-sky]

Hi, thanks for the reminder!

This PR is a small documentation fix for incorrect FSDP config examples in the README (specifically fsdp_auto_wrap_policy and the space in fsdp_transformer_layer_cls_to_wrap). It doesn't fix a tracked issue.

Could a maintainer please add the no-issue-needed label? Thank you!

Hi @Thundermean-sky, thanks for the PR! It does not appear to link an issue it fixes. If this PR addresses an existing issue, please add a closing keyword (e.g. Fixes #1234) to the PR description so the issue is linked. See the contribution guide for more details. If this PR intentionally does not fix a tracked issue, a maintainer can add the no-issue-needed label to silence this reminder.

Please note that PRs without a linked issue are likely to be automatically closed 10 days after this notice.

Once the PR links an issue (or gets the no-issue-needed label), you can ignore this message — it stays here as a comment, but it no longer applies.