lint: api: sort imports

After configuring sort behavior in isort.cfg, run `./scripts/isort`
on all the api/ modules in the tree.

BUG=b:187788732
TEST=`cros lint` is clean

Change-Id: I838009ea70ff52a1560a597509909c0b514247b5
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/chromite/+/3615052
Commit-Queue: Mike Frysinger <vapier@chromium.org>
Tested-by: Mike Frysinger <vapier@chromium.org>
Reviewed-by: Alex Klein <saklein@chromium.org>
diff --git a/api/controller/dependency.py b/api/controller/dependency.py
index 1c7bfa6..3eb2884 100644
--- a/api/controller/dependency.py
+++ b/api/controller/dependency.py
@@ -13,6 +13,7 @@
 from chromite.api import validate
 from chromite.api.controller import controller_util
 from chromite.api.gen.chromite.api import depgraph_pb2
+
 # TODO(crbug/1081828): stop using build_target and drop it from the proto.
 from chromite.lib import build_target_lib
 from chromite.lib.parser import package_info