Apply suggested fix to src/bosh-nats-sync/spec/nats_sync/users_sync_spec.rb from Copilot Autofix

Co-authored-by: Copilot Autofix powered by AI <223894421+github-code-quality[bot]@users.noreply.github.com>

Author: rkoster

src/bosh-nats-sync/spec/nats_sync/users_sync_spec.rb

@@ -316,7 +316,7 @@ module NATSSync
           end
         end
 
-        describe 'when there are running vms in Bosh and there are is no subject information for hm or the director' do
+        describe 'when there are running vms in Bosh and there is no subject information for hm or the director' do
           let(:director_subject_file) { '/file/nonexistent1' }
           let(:hm_subject_file) { '/file/nonexistent2' }