Stop unnecessary index exists checks on _edit_lock meta updates

[sathyapulse]

Description

The _edit_lock meta key is not indexed, so there is no need to check if the ES index exists.
This change removes the unnecessary index exists checks to reduce the load on the ES server.

Stack trace of the index request

[
  {
    "file": "/wp/wp-content/mu-plugins/search/elasticpress/includes/classes/Elasticsearch.php",
    "line": 1029,
    "function": "remote_request",
    "class": "ElasticPress\\Elasticsearch",
    "type": "->"
  },
  {
    "file": "/wp/wp-content/mu-plugins/search/elasticpress/includes/classes/Indexable.php",
    "line": 320,
    "function": "index_exists",
    "class": "ElasticPress\\Elasticsearch",
    "type": "->"
  },
  {
    "file": "/wp/wp-content/mu-plugins/search/includes/classes/class-search.php",
    "line": 2221,
    "function": "index_exists",
    "class": "ElasticPress\\Indexable",
    "type": "->"
  },
  {
    "file": "/wp/wp-includes/class-wp-hook.php",
    "line": 324,
    "function": "do_not_sync_if_no_index",
    "class": "Automattic\\VIP\\Search\\Search",
    "type": "->"
  },
  {
    "file": "/wp/wp-includes/plugin.php",
    "line": 205,
    "function": "apply_filters",
    "class": "WP_Hook",
    "type": "->"
  },
  {
    "file": "/wp/wp-content/mu-plugins/search/elasticpress/includes/classes/SyncManager.php",
    "line": 289,
    "function": "apply_filters"
  },
  {
    "file": "/wp/wp-content/mu-plugins/search/elasticpress/includes/classes/Indexable/Post/SyncManager.php",
    "line": 151,
    "function": "kill_sync",
    "class": "ElasticPress\\SyncManager",
    "type": "->"
  },
  {
    "file": "/wp/wp-includes/class-wp-hook.php",
    "line": 324,
    "function": "action_queue_meta_sync",
    "class": "ElasticPress\\Indexable\\Post\\SyncManager",
    "type": "->"
  },
  {
    "file": "/wp/wp-includes/class-wp-hook.php",
    "line": 348,
    "function": "apply_filters",
    "class": "WP_Hook",
    "type": "->"
  },
  {
    "file": "/wp/wp-includes/plugin.php",
    "line": 517,
    "function": "do_action",
    "class": "WP_Hook",
    "type": "->"
  }
]

Changelog Description

Added

Removed

Fixed

• Remove index exists checks for disallowed meta keys, specifically the _edit_lock key.

Changed

Pre-review checklist

Please make sure the items below have been covered before requesting a review:

• This change works and has been tested locally or in Codespaces (or has an appropriate fallback).
• This change works and has been tested on a sandbox.
• This change has relevant unit tests (if applicable).
• This change uses a rollout method to ease with deployment (if applicable - especially for large scale actions that require writes).
• This change has relevant documentation additions / updates (if applicable).
• I've created a changelog description that aligns with the provided examples.

Pre-deploy checklist

• VIP staff: Ensure any alerts added/updated conform to internal standards (see internal documentation).

Steps to Test

[codecov]

Codecov Report

Attention: Patch coverage is 58.33333% with 5 lines in your changes missing coverage. Please review.

Project coverage is 30.55%. Comparing base (147c588) to head (7fe0523).

Files with missing lines	Patch %	Lines
search/includes/classes/class-search.php	58.33%	5 Missing ⚠️

Additional details and impacted files

@@              Coverage Diff              @@
##             develop    #6021      +/-   ##
=============================================
+ Coverage      30.52%   30.55%   +0.03%     
- Complexity      4811     4819       +8     
=============================================
  Files            289      289              
  Lines          21175    21175              
=============================================
+ Hits            6463     6471       +8     
+ Misses         14712    14704       -8     

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[rebeccahum]

Thank you for the PR, however, we already cache the index_exists requests into an option:

vip-go-mu-plugins/search/includes/classes/class-search.php

Lines 869 to 873 in 147c588

	if ( false !== $cached_index_exists_request ) {
	$cached_index_exists_response_code = (int) wp_remote_retrieve_response_code( $cached_index_exists_request );
	if ( 'index_exists' === $type && in_array( $cached_index_exists_response_code, $valid_index_exists_response_codes, true ) ) {
	// Return cached index_exists option.
	return $cached_index_exists_request;

. So I'm not too worried about attempting to make that request since it will always be intercepted.