Fix wecom integration dropdown menu bug in the config page

What does this MR do and why?

Related issue: #4289 (closed)

Fix wecom integration dropdown menu bug in the config page

Broken by previous refactor MR: !1992 (merged)

It refactored the menu definition from:

{
          type: 'select',
          name: 'labels_to_be_notified_behavior',
          title: s_('JH|INTEGRATION|Labels to be notified behavior'),
          choices: [
            [s_('JH|INTEGRATION|Match any of the labels'), MATCH_ANY_LABEL],
            [s_('JH|INTEGRATION|Match all of the labels'), MATCH_ALL_LABELS]
          ]
        }

to

field :labels_to_be_notified_behavior,
      type: :select,
      title: -> { s_('JH|INTEGRATION|Labels to be notified behavior') },
      choices: [
        [-> { s_('JH|INTEGRATION|Match any of the labels') }, MATCH_ANY_LABEL],
        [-> { s_('JH|INTEGRATION|Match all of the labels') }, MATCH_ALL_LABELS]
      ]