Add group consistency check to domain template deletion

[t4niwa]

Description

Add group consistency check to domain template deletion. #3273

Contribution Checklist:

• The pull request does not introduce any breaking changes
• I have read the contribution guidelines.
• Create an issue and link to the pull request.

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[gemini-code-assist]

Code Review

This pull request introduces a consistency check in the deleteDomainTemplate method to ensure that template groups are not referenced by roles in other domains before a template is deleted. The review feedback suggests adding a null check for group objects within the template iteration to handle potential misconfigurations in the solution_templates.json file, which improves robustness and aligns with configuration logging standards.

[gemini-code-assist]

To improve robustness and adhere to the repository's configuration handling rules, add a null check for the group object. Since solution_templates.json is a configuration file, any null or invalid entries should be logged as an ERROR to signal a clear misconfiguration.

            for (Group group : template.getGroups()) {
                if (group == null) {
                    LOG.error("Invalid configuration: null group entry found in solution_templates.json");
                    continue;
                }
                String groupName = group.getName().replace("_domain_", domainName);
                groupMemberConsistencyCheck(domainName, groupName, true, caller);
            }

References

1. If a configuration property is defined but results in an empty or invalid value, it should be logged as an ERROR to signal a clear misconfiguration.

[havetisyan]

@t4niwa please add tests cases for the new code. any new line in any of the servers or shared libraries must be fully covered with an appropriate test case