message: AlertManager YAML Editor: Allow textarea to be empty, error on empty yaml
diff: @@ -22,6 +22,11 @@ const AlertManagerYAMLEditor: React.FC<AlertManagerYAMLEditorProps> = ({obj, onC
  const save = e => {
  e.preventDefault();
  + if (_.isEmpty(yamlStringData)) {
  + setErrorMsg('Alertmanager configuration cannot be empty.');
  + setSuccessMsg('');
  + return;
  + }
  setInProgress(true);
  const patch = [{ op: 'replace', path: '/data/alertmanager.yaml', value: Base64.encode(yamlStringData)}];
  k8sPatch(SecretModel, secret, patch)
  @@ -44,7 +49,7 @@ const AlertManagerYAMLEditor: React.FC<AlertManagerYAMLEditorProps> = ({obj, onC
  <p className="co-alert-manager-yaml__explanation">
  Update this YAML to configure Routes, Receivers, Groupings and other Alertmanager settings
  </p>
  - {!_.isEmpty(yamlStringData) && <div className="co-alert-manager-yaml__form-entry-wrapper">
  + <div className="co-alert-manager-yaml__form-entry-wrapper">
  <div className="co-alert-manager-yaml__form">
  <div className="form-group">
  <DroppableFileInput
  @@ -54,12 +59,11 @@ const AlertManagerYAMLEditor: React.FC<AlertManagerYAMLEditorProps> = ({obj, onC
  </div>
  </div>
  </div>
  - }
  <ButtonBar errorMessage={errorMsg} successMessage={successMsg} inProgress={inProgress}>
  <ActionGroup className="pf-c-form">
  - {!_.isEmpty(yamlStringData) && <Button type="submit" variant="primary" id="save-changes">
  + <Button type="submit" variant="primary" id="save-changes">
  Save
  - </Button> }
  + </Button>
  <Button type="button" variant="secondary" id="cancel" onClick={onCancel}>
  Cancel
  </Button>
  