Backport of fix: validate replace_triggered_by attribute references into v1.14

[github-actions]

Backport

This PR is auto-generated from #38010 to be assessed for backporting due to the inclusion of the label 1.14-backport.

The below text is copied from the body of the original PR.

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Summary

• replace_triggered_by now reports an error when given an invalid attribute reference that does not exist in the target resource

Test plan

• Added unit test TestContext2Plan_triggeredByInvalidAttribute
• Existing replace_triggered_by tests pass
• Manual testing with null_resource confirms invalid references now produce errors
• Valid attribute references continue to work correctly

Fixes #36740

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Overview of commits

• d68e029

• f595598

[github-actions]

Changelog Warning

Currently this PR would target a v1.15 release. Please add a changelog entry for in the .changes/v1.15 folder, or discuss which release you'd like to target with your reviewer. If you believe this change does not need a changelog entry, please add the 'no-changelog-needed' label.

[SarahFrench]

Changelog Warning

Currently this PR would target a v1.15 release. Please add a changelog entry for in the .changes/v1.15 folder, or discuss which release you'd like to target with your reviewer. If you believe this change does not need a changelog entry, please add the 'no-changelog-needed' label.

This automation needs fixing 😭 - I've moved the change file into the correct folder for the base branch

[jbardin]

I think the automation worked correctly here. This was targeted for 1.15, so shouldn't have a backport. If this were intended for 1.14 the changelog should only be for that one version.

We do however have a problem in the rare case that a patch needs to be in two minor versions at once. There we currently have to manually backport each version to avoid the conflicting changlog entries from failing the check.