UI 1817 disable create target name space if name space is flux system

[ahussein3]

• Resolve [UI] Add kustomization with Create target namespace for kustomization option fails for 'flux-system' target namespace #1817

What Changes:

• Disable the target checkbox if target namespace field is = flux-system
• Add tooltip when checkbox is disabled

[AlinaGoaga]

Looking great, approved! Added a suggestion for the adding of the var but it's the same thing, happy to merge as is

    currentAutomation[index] = {
      ...automation,
      [fieldName as string]: value,
    };

    if (fieldName === 'target_namespace' && value === 'flux-system') {
      currentAutomation[index] = {
        ...currentAutomation[index],
        createNamespace: false,
      };
    }