Add tests for checking DBT_ENV_SECRET_s don't break logging

[CT-1783](#6568) describes
a bug in dbt-core 1.0-1.3 wherein when a `DBT_ENV_SECRET_` all
`{{ log("logging stuff", info=True) }}` invocations break. This commit
adds a test for this for two reasons:
1. Ensure we don't regress to this behavior going forward
2. Act as a base commit for making the backport fixes to dbt-core 1.0-1.3

test/unit/test_base_context.py

@@ -1,3 +1,5 @@
+import os
+
 from dbt.context.base import BaseContext
 from jinja2.runtime import Undefined
 
@@ -10,3 +12,11 @@ def test_log_jinja_undefined(self):
             BaseContext.log(msg=Undefined(), info=True)
         except Exception as e:
             assert False, f"Logging an jinja2.Undefined object raises an exception: {e}"
+
+    def test_log_with_dbt_env_secret(self):
+        # regression test for CT-1783
+        try:
+            os.environ["DBT_ENV_SECRET_LOG_TEST"] = "cats_are_cool"
+            BaseContext.log({"fact1": "I like cats"}, info=True)
+        except Exception as e:
+            assert False, f"Logging while a `DBT_ENV_SECRET` was set raised an exception: {e}"