Decodes a binary vector entity field (base64 of little-endian float32 bytes).
Parameters
base64: string|null|undefined
The field value; null / undefined are allowed.
Returns Float32Array<ArrayBufferLike>|null
The vector, or null when the value is missing, not valid base64, empty, or not a
whole number of float32 values. Callers usually fall back to a JSON copy of the vector.
Decodes a binary vector entity field (base64 of little-endian float32 bytes).