group_by_package errors when packages start with `import`

[glasnt]

group_by_package is a configuration only used by the google profile, but it introduces a pathway in section_key where from imports are further filtered.

The current tokenization logic for this works for most cases, except where the imported module starts with import.

Failure case: applying isort --profile google yielded the following diff:

--- a/kms/snippets/snippets_test.py
+++ b/kms/snippets/snippets_test.py
 from encrypt_symmetric import encrypt_symmetric
+from import_manually_wrapped_key import import_manually_wrapped_key
 from generate_random_bytes import generate_random_bytes
 from get_key_labels import get_key_labels
 from get_key_version_attestation import get_key_version_attestation
@@ -65,7 +67,6 @@ from get_public_key_jwk import get_public_key_jwk
 from iam_add_member import iam_add_member
 from iam_get_policy import iam_get_policy
 from iam_remove_member import iam_remove_member
-from import_manually_wrapped_key import import_manually_wrapped_key
 from quickstart import quickstart

The import of import_manually_wrapped_key was erroneously moved.

Patch and tests incoming.

[glasnt]

ref #1486
b583c12#diff-153ebbc261312b467290ff2b9bf2d722dfb3e41c2db70aa60c8128ad66bd05cd