SearchIndex.from_existing assumes only 1 prefix

[justin-cechmanek]

When an index is defined with multiple prefixes such as:

IndexDefinition(prefix=["AA","BB","CC"], index_type=IndexType.HASH)

and we call .from_existing(..) the returned index is:
"index": {
"name": "index:test",
"prefix": "AA",
"key_separator": ":",
"storage_type": "hash"
},

Looks like this line is always grabbing just the first entry from a list of prefixes
https://github.com/redis/redis-vl-python/blob/main/redisvl/redis/connection.py#L87