Relax the custom git config check for Geo secondaries

lib/system_check/app/git_user_default_ssh_config_check.rb

@@ -10,10 +10,10 @@ module SystemCheck
       ].freeze
 
       set_name 'Git user has default SSH configuration?'
-      set_skip_reason 'skipped (git user is not present or configured)'
+      set_skip_reason 'skipped (Geo secondary, or git user is not present / configured)'
 
       def skip?
-        !home_dir || !File.directory?(home_dir)
+        Gitlab::Geo.secondary? || !home_dir || !File.directory?(home_dir)
       end
 
       def check?

spec/lib/system_check/app/git_user_default_ssh_config_check_spec.rb

@@ -34,6 +34,15 @@ describe SystemCheck::App::GitUserDefaultSSHConfigCheck do
 
       it { is_expected.to eq(expected_result) }
     end
+
+    # EE-only
+    it 'skips Geo secondaries' do
+      stub_user
+      stub_home_dir
+      allow(Gitlab::Geo).to receive(:secondary?).and_return(true)
+
+      is_expected.to be_truthy
+    end
   end
 
   describe '#check?' do