Reintegrate functional adapter tests into GitHub Action CI

[dataders]

I might be lost in tox here, but as far as I can tell, there are tox jobs setup to run the dbt-core's integration test suite, but I don't see them being run in a PR's CI, only the unit tests (which are incredible and very comprehensive btw!)

dbt-databricks/tox.ini

Lines 30 to 64 in e921754

	[testenv:integration-databricks-cluster]
	basepython = python3
	commands = /bin/bash -c '{envpython} -m pytest -v --profile databricks_cluster -n4 tests/functional/adapter/* {posargs}; ret=$?; [ $ret = 5 ] && exit 0 || exit $ret'
	/bin/bash -c '{envpython} -m pytest -v -m profile_databricks_cluster -n4 tests/integration/* {posargs}; ret=$?; [ $ret = 5 ] && exit 0 || exit $ret'
	passenv = DBT_* PYTEST_ADDOPTS
	deps =
	-r{toxinidir}/dev-requirements.txt
	-r{toxinidir}/requirements.txt
	[testenv:integration-databricks-uc-cluster]
	basepython = python3
	commands = /bin/bash -c '{envpython} -m pytest -v --profile databricks_uc_cluster -n4 tests/functional/adapter/* {posargs}; ret=$?; [ $ret = 5 ] && exit 0 || exit $ret'
	/bin/bash -c '{envpython} -m pytest -v -m profile_databricks_uc_cluster -n4 tests/integration/* {posargs}; ret=$?; [ $ret = 5 ] && exit 0 || exit $ret'
	passenv = DBT_* PYTEST_ADDOPTS
	deps =
	-r{toxinidir}/dev-requirements.txt
	-r{toxinidir}/requirements.txt
	[testenv:integration-databricks-sql-endpoint]
	basepython = python3
	commands = /bin/bash -c '{envpython} -m pytest -v --profile databricks_sql_endpoint -n4 tests/functional/adapter/* {posargs}; ret=$?; [ $ret = 5 ] && exit 0 || exit $ret'
	/bin/bash -c '{envpython} -m pytest -v -m profile_databricks_sql_endpoint -n4 tests/integration/* {posargs}; ret=$?; [ $ret = 5 ] && exit 0 || exit $ret'
	passenv = DBT_* PYTEST_ADDOPTS
	deps =
	-r{toxinidir}/dev-requirements.txt
	-r{toxinidir}/requirements.txt
	[testenv:integration-databricks-uc-sql-endpoint]
	basepython = python3
	commands = /bin/bash -c '{envpython} -m pytest -v --profile databricks_uc_sql_endpoint -n4 tests/functional/adapter/* {posargs}; ret=$?; [ $ret = 5 ] && exit 0 || exit $ret'
	/bin/bash -c '{envpython} -m pytest -v -m profile_databricks_uc_sql_endpoint -n4 tests/integration/* {posargs}; ret=$?; [ $ret = 5 ] && exit 0 || exit $ret'
	passenv = DBT_* PYTEST_ADDOPTS
	deps =
	-r{toxinidir}/dev-requirements.txt
	-r{toxinidir}/requirements.txt

[dataders]

resolved by: #274