Summary:
Random test with big amount of rows and dimensions for vector index
Jira: DB-14638

Test Plan: PgVectorIndexTest.Random/*

Reviewers: aleksandr.ponomarenko, arybochkin

Reviewed By: aleksandr.ponomarenko

Subscribers: ybase, yql

Tags: #jenkins-ready

Differential Revision: https://phorge.dev.yugabyte.com/D40845