Currently, when running `explain` on a vector search, all the vector embeddings are included. 

These can be and often are extremely lengthy. E.g., the vector embeddings for mflix data look like this, where there are over 1000 elements. This makes the explain output extremely cumbersome to read.

When running explain on a basic $unionWith $vectorSearch (as part of SERVER-88046, so using the real mongot rather than a mock):

On a sharded cluster:

• The explain output on a is over 9000 lines long.
• The actual vector we're searching for has its embeddings included 6 separate times in the output (which is questionable in and of itself), and so the length of explain reduces to ~420 lines when you remove the embeddings.

On a single node:

• Explain output is ~4800 lines long.
• The vector embedding is included 3 times, length reduces to ~200 lines without the embeddings.