fix registry tests to not hard code values because that's fragile

[andyk]

See, e.g.,

agentos/tests/test_specs.py

Lines 31 to 40 in 74b0cb6

	def test_flatten_versioned_spec():
	reg = Registry.from_yaml(GH_SB3_AGENT_DIR / "components.yaml")
	rand_comp_spec = reg.get_component_spec("agent", "test_staging")
	assert "agent==test_staging" in rand_comp_spec.keys()
	assert rand_comp_spec["agent==test_staging"]["repo"] == "aos_github"
	flattened = flatten_spec(rand_comp_spec)
	assert flattened["identifier"] == "agent==test_staging"
	assert flattened["name"] == "agent"
	assert flattened["version"] == "test_staging"

Instead of hard coding strings in our assert statements like "agent==test_staging", "agent", and "test_staging", we should read the yaml file directly and compare the results of

YAML -> registry object -> API to get spec value from Registry 

TO

loading values from the YAML file directly.