Fix vector embedding typo in help description of "az cosmosdb create"

### Describe the bug

There is a typo in our az cli help file for az cosmosdb create. to create vector embeddings message says "vector encryption" in help message.

### Related command

`az cosmosdb create`

### Errors

there is no error, just need to fix help message

### Issue script & Debug output

not needed since there is no error and fix in script functioning

### Expected behavior

"Vector Embedding Policy" in place of "Vector Encryption Policy"

### Environment Summary

NA

### Additional context

_No response_