test/isort: apply diff to full tree

Apply the isort modifications to the entire source tree, not just the
selected python files of test-src.

Signed-off-by: David Rheinsberg <david.rheinsberg@gmail.com>

devices/org.osbuild.loopback

@@ -20,14 +20,11 @@ documentation for `osbuil.util.udev.UdevInhibitor`.
 import argparse
 import os
 import sys
-
 from typing import Dict
 
-from osbuild import devices
-from osbuild import loop
+from osbuild import devices, loop
 from osbuild.util.udev import UdevInhibitor
 
-
 SCHEMA = """
 "additionalProperties": false,
 "required": ["filename"],

devices/org.osbuild.luks2

@@ -19,13 +19,11 @@ import stat
 import subprocess
 import sys
 import uuid
-
 from typing import Dict, Optional
 
 from osbuild import devices
 from osbuild.util.udev import UdevInhibitor
 
-
 SCHEMA = """
 "additionalProperties": false,
 "required": ["passphrase"],

devices/org.osbuild.lvm2.lv

@@ -34,12 +34,10 @@ import stat
 import subprocess
 import sys
 import time
-
 from typing import Dict, Tuple, Union
 
 from osbuild import devices
 
-
 SCHEMA = """
 "additionalProperties": false,
 "required": ["volume"],