Fixes thumbnail cards not loading the preview image

Reduce grid rows if larger than number of images available

When a set number of grid rows is specified in settings, then it leads
to situations where an entire row in the grid is empty.
The most noticable example is the processing preview when the row count
is set to 2, where it shows the preview just fine but with a black
rectangle under it.

Fixes X/Y/Z Plot parameters not being restored from images

Fix embeddings, upscalers, and refactor `--upcast-sampling`

Css fixes

Fix error when using img2img batch without masks

fixed a bug where after switching to a checkpoint with unknown hash, you'd get empty space instead of checkpoint name in UI
fixed a bug where if you update a selected checkpoint on disk and then restart the program, a different checkpoint loads, but the name is shown for the the old one.

The torch.narrow fix was required for nightly PyTorch builds for a while to prevent a hard crash, but newer nightly builds don't have this issue.

Apparently the version of PyTorch macOS users are currently at doesn't always handle half precision VAEs correctly. We will probably want to update the default PyTorch version to 2.0 when it comes out which should fix that, and at this point nightly builds of PyTorch 2.0 are going to be recommended for most Mac users. Unfortunately someone has already reported that their M2 Mac doesn't work with the nightly PyTorch 2.0 build currently, so we can add --no-half-vae for now and give users that can install nightly PyTorch 2.0 builds a webui-user.sh configuration that overrides the default.

Ask user to clarify conditions

Allow users to convert models to Instruct-pix2pix models by supporting merging Instruct-pix2pix models with regular ones in the merge tab

don't replace regular --help with new paths.py parser help

Add a Python version check