feat: delete vectors with metadata filter and id prefix

[heyjorgedev]

This PR introduces the ability to delete vectors from our index by using ids, id prefix and metadata filters.

Delete Vectors by Id or ids:

// delete multiple records
$index->delete(['users:1', 'users:2']);

// delete single record
$index->delete('users:1');

Delete Vectors by prefix

use Upstash\Vector\VectorDeleteByPrefix;

$index->delete(new VectorDeleteByPrefix('users:'));

Delete Vectors by metadata filter

use Upstash\Vector\VectorDeleteByMetadataFilter;

$index->delete(new VectorDeleteByMetadataFilter('salary > 1000'));

[linear]

DX-1666 PHP: Support delete with metadata filter & id prefix for Vector PHP