Embedding Projector: UMAP and TSNE projections broken for embeddings that are not normalized

Chrome 111.0.5563.64

Issue description

When using embeddings that are not normalized and sphereized, the UMAP and T-SNE are incorrect or not simply loading.
See #5547 for a previous bug report.

the reason is that knn expects normalized vectors for cosine distance (cosDistNorm) rather than arbitrary vectors.

• Build and launch projector (must be from master, not https://projector.tensorflow.org)
• Select Iris demo tensor dataset
• Keep "Sphereize data" unchecked
• change projection type to T-SNE
• The end result is different from what happens when using https://projector.tensorflow.org/
• change projection tyoe to UMAP
• See "Initialize UMAP..." modal loading forever

Alternative repo:

• Build and launch projector (must be from master, not https://projector.tensorflow.org)
• Uncheck "Sphereize data" on the default Word2Vec 10k dataset
• Switch projection from "PCA" to either t-SNE or UMAP
• See the UI breaks with "Initializing t-SNE..."/"Initialize UMAP..." modal loading forever

related to: #2421

Start with tensorboard/plugins/projector/vz_projector/data.ts around the cited knn cosine-distance logic, then follow the projector build instructions in tensorboard/plugins/projector/README.md. Reproduce the Iris or Word2Vec 10k case with Sphereize data unchecked and compare T-SNE and UMAP behavior; done means both projections initialize and produce the expected result for non-normalized embeddings.