Fix GROUP reserved keyword handling for new union_data use case

[fivetran-jamie]

PR Overview

This PR will address the following Issue/Feature:
https://getdbt.slack.com/archives/C01D1R2JLLA/p1733513338340409

This PR will result in the following new package version:

0.14.1

Please provide the finalized CHANGELOG entry which details the relevant changes included in this PR:

Bug Fixes

• In v0.19.0, Snowflake users may have seen when searching for a relation, dbt found an approximate match errors when running the stg_zendesk__group_tmp model. We have updated the reserved keyword handling of the group source table and adjusted its quoting in order to eradicate this issue.

PR Checklist

Basic Validation

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• dbt run –full-refresh && dbt test
• dbt run (if incremental models are present) && dbt test

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• The appropriate issue has been linked, tagged, and properly assigned
• All necessary documentation and version upgrades have been applied
• docs were regenerated (unless this PR does not include any code or yml updates)
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