analytics: don't verify config from repo

Otherwise this will raise an exception from analytics worker:
```
dvc config cache.type sometypo
```
But running that same command with `--system` or `--global` flag outside
of repo won't raise that.

Also need to better handle ConfigObjError, but that is a separate issue.

tests/unit/test_analytics.py

@@ -0,0 +1,14 @@
+from dvc.analytics import Analytics
+from dvc.config import Config
+from dvc.repo import NotDvcRepoError
+
+
+def test_broken_config(mocker, dvc_repo):
+    Config(dvc_repo.dvc_dir, validate=False).set("cache", "type", "unknown")
+
+    assert Analytics._get_current_config()
+
+    with mocker.patch(
+        "dvc.repo.Repo.find_dvc_dir", side_effect=NotDvcRepoError(".")
+    ):
+        assert Analytics._get_current_config()