[opendistro-1.12][backport] Add validation for null elements in JSON array (#1157)

[afazel]

(cherry picked from commit 960d420)

opensearch-security pull request intake form

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1. Category: (Enhancement, New feature, Bug fix, Test fix, Refactoring, Maintenance, Documentation)

2. Github Issue # or road-map entry, if available:

3. Description of changes:

4. Why these changes are required?

5. What is the old behavior before changes and new behavior after changes? (Please add any example/logs/screen-shot if available)

6. Testing done: (Please provide details of testing done: Unit testing, integration testing and manual testing)

7. TO-DOs, if any: (Please describe pending items and provide Github issues# for each of them)

8. Is it backport from main branch? (If yes, please add backport PR # and commits #)

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[codecov-commenter]

Codecov Report

Merging #1360 (a9bda6f) into opendistro-1.12 (1d2857e) will increase coverage by 0.01%.
The diff coverage is 100.00%.

@@                  Coverage Diff                  @@
##             opendistro-1.12    #1360      +/-   ##
=====================================================
+ Coverage              64.63%   64.65%   +0.01%     
- Complexity              3217     3226       +9     
=====================================================
  Files                    246      246              
  Lines                  17200    17220      +20     
  Branches                3048     3055       +7     
=====================================================
+ Hits                   11118    11134      +16     
- Misses                  4538     4541       +3     
- Partials                1544     1545       +1     

Impacted Files	Coverage Δ
...est/validation/AbstractConfigurationValidator.java	83.89% <100.00%> (+2.49%)	⬆️
...security/configuration/DlsFlsFilterLeafReader.java	59.76% <0.00%> (-0.71%)	⬇️
...search/security/tools/OpenDistroSecurityAdmin.java	47.26% <0.00%> (-0.27%)	⬇️
.../dlic/auth/ldap2/LDAPConnectionFactoryFactory.java	57.25% <0.00%> (+0.76%)	⬆️

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