[BUGFIX]- Central Reporting Erroring Out Fix and GR13 addition to aggregation

[singhgss]

This PR fixes/adds/changes/removes

fixes #346 #350

1. Adds aggregation for GR13 in the ingestion script.
2. Implements a fix using column_ifexists to prevent missing column errors in Central Reporting.
3. Ensures backward compatibility for customers using older CaC versions.
4. Added additional check so queries are not executed against central reporting tenant itself.

Breaking Changes

None. This update ensures compatibility with both older and newer CaC versions.

Testing Evidence

1. Successfully tested ingestion script with v2.x.x and verified GR13 aggregation.
2. Verified that using column_ifexists prevents errors in older CaC versions.
3. Conducted end-to-end testing to ensure CentralView aggregation does not break on missing fields.

As part of this Pull Request I have

• Checked for duplicate Pull Requests
• Associated it with relevant GitHub Issues
• Ensured my code/branch is up-to-date with the latest changes in the main branch
• Performed testing and provided evidence.
• Updated relevant and associated documentation.
• Ensured PowerShell module versions have been updated (manually or with the ./tools/Update-ModuleVersions.ps1 script)