Fixed /_index_template/_simulate*.

[dblock]

Description

Fixed /_index_template/_simulate*, added tests.

Issues Resolved

Part of #663.

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[github-actions]

Changes Analysis

Commit SHA: 73d547d
Comparing To SHA: c888a16

API Changes

Summary

├─┬Paths
│ └─┬/_index_template/_simulate_index/{name}
│   └─┬POST
│     ├──[➖] parameters (21167:13)❌ 
│     └──[➖] parameters (21183:13)❌ 
└─┬Components
  ├──[➖] parameters (21182:7)❌ 
  ├──[➖] parameters (21167:7)❌ 
  └─┬indices.simulate_template___Template
    └──[➖] required (50809:11)❌ 

Document Element	Total Changes	Breaking Changes
paths	2	2
components	3	3

• ❌ BREAKING Changes: 5 out of 5
• Removals: 5
• Breaking Removals: 5

Report

The full API changes report is available at: https://github.com/opensearch-project/opensearch-api-specification/actions/runs/12036128911/artifacts/2240351807

API Coverage

	Before	After	Δ
Covered (%)	599 (58.67 %)	599 (58.67 %)	0 (0 %)
Uncovered (%)	422 (41.33 %)	422 (41.33 %)	0 (0 %)
Unknown	42	42	0

[github-actions]

Spec Test Coverage Analysis

Total	Tested
528	400 (75.76 %)