Fix migrate -f command to work with comments

Signed-off-by: Matheus Pimenta <matheuscscp@gmail.com>

cmd/flux/testdata/migrate/file-system/dir/some-file.yaml

@@ -7,6 +7,13 @@ kind: ImageRepository
 apiVersion: image.toolkit.fluxcd.io/v1beta2
 kind: ImagePolicy
 
+---
+spec:
+  wait: true
+  dependsOn:
+    - apiVersion: image.toolkit.fluxcd.io/v1beta1 # update this from v1beta1
+      kind: ImageRepository
+
 
 ---