[Code scan] Add direct test-runner dependencies to the test extra

[njzjz]

Found by Codex global repository scan of deepmodeling/dpgen2 at commit 2679611a3704f5c2646c8cb353e34177518db758.

The test extra only installs two packages:

dpgen2/pyproject.toml

Lines 59 to 62 in 2679611

	test = [
	'fakegaussian>=0.0.3',
	'dpgui',
	]

CI has to install additional test-runner dependencies separately:

dpgen2/.github/workflows/test.yml

Lines 21 to 26 in 2679611

	- name: Install dependencies
	run: |
	pip install -e .[test]
	pip install mock coverage pytest
	- name: Test
	run: SKIP_UT_WITH_DFLOW=0 DFLOW_DEBUG=1 coverage run --source=./dpgen2 -m unittest -v -f && coverage report

The tests import packages that are not in the test extra, including mock, pytest, and jsonpickle:

dpgen2/tests/exploration/test_report_adaptive_lower.py

Line 8 in 2679611

import mock

dpgen2/tests/utils/test_bohrium_config.py

Line 14 in 2679611

import pytest

dpgen2/tests/test_dpgen_loop.py

Line 16 in 2679611

import jsonpickle

This makes pip install -e .[test] insufficient for contributors to run the advertised tests locally.

Suggested fix: add direct test dependencies to the test extra and simplify CI to install the package with that extra only.