Cherry-pick #25516 to 7.x: Fix Insert when array is empty

[michalpristas]

Cherry-pick of PR #25516 to 7.x branch. Original message:

What does this PR do?

Calling Insert on inputs.0.sub fails when array we're inserting into is empty.
This PRs handles this and creates a node instead.
If the inserted node is not needed it's excluded using type filter later on.

Why is it important?

#24453

Checklist

• My code follows the style guidelines of this project
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have made corresponding change to the default configuration files
• I have added tests that prove my fix is effective or that my feature works
• I have added an entry in CHANGELOG.next.asciidoc or CHANGELOG-developer.next.asciidoc.

cc @michel-laterman

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• Build Cause: Pull request #25543 opened

• Start Time: 2021-05-05T10:05:10.547+0000

• Duration: 98 min 22 sec

• Commit: 5428c19

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Failed	0
Passed	6773
Skipped	31
Total	6804

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Test	Results
Failed	0
Passed	6773
Skipped	31
Total	6804