Summary:
Timeline:

D34040 introduced an optimization to skip redundant index updates and foreign key checks.
D37746 gated this feature behind a preview flag (feature is OFF by default) named yb_update_optimization_infra.
D37749 introduced a feature enablement flag ysql_yb_skip_redundant_update_ops, and promoted the above preview flag to an auto flag.
D40300 turned OFF the feature via the enablement flag ysql_yb_skip_redundant_update_ops due to the bug GH-25075.
D40404 fixed the above bug.

This revision turns ON the feature by default by turning ON the feature enablement flag ysql_yb_skip_redundant_update_ops.
This reverts commit 05293919e3f62b266d1d13b0b15601bdad480557 (D40300).
Jira: DB-7701

Test Plan: Run Jenkins

Reviewers: amartsinchyk, smishra

Reviewed By: amartsinchyk

Subscribers: ybase, yql

Tags: #jenkins-ready

Differential Revision: https://phorge.dev.yugabyte.com/D40649