fix: Add identifier and schema to get_relation_last_modified macro

[xcezz]

Summary

The get_relation_last_modified macro currently returns an invalid data structure, causing compilation errors when running dbt source freshness.

This PR adds identifier and schema columns and keeps the existing data structure expected by dbt.

Description

After updating dbt and dbt-dremio from 1.7 to 1.8, I noticed that freshness checks no longer work:

20:41:23    Compilation Error in source <SOURCE> (models/sources.yml)
  Got an invalid result from "get_relation_last_modified" macro: [(datetime.datetime(2025, 1, 31, 20, 13, 6), datetime.datetime(2025, 1, 31, 20, 41, 22))]

After reading dbt-labs/dbt-core#8307, especially looking at the get_relation_last_modified reference implementation from Snowflake, I noticed we don't return

• schema and
• identifier

With this change, dbt source freshness returns proper freshness information without compilation errors.

Test Results

Changelog

• Added a summary of what this PR accomplishes to CHANGELOG.md

Related Issue

[howareyouman]

@xcezz Hey!
Thank you for your contribution!
Before merging this PR, please sign Contributor License Agreement, enabling Dremio to distribute your contribution without restriction.
Thank you beforehand!

[wobu]

some additional context:
in this dbt-adapters PR: dbt-labs/dbt-adapters#127
they introduces the usage and requirement of the 'schema' and 'identifier' field

[bcmeireles]

Thanks for the contribution!
I see in this PR's CI run that this actually solves one of our known failures in the tests. Could you also please update .github/expected_failures by removing:

tests/functional/adapter/relation/test_get_relation_last_modified.py::TestGetLastRelationModified::test_get_last_relation_modified

Thanks :)

[howareyouman]

@xcezz Hey! Have you already signed CLA? Our colleagues haven't received any new CLA signs yet.

[xcezz]

@xcezz Hey! Have you already signed CLA? Our colleagues haven't received any new CLA signs yet.

I thought I had already done that. I've just signed it again!