Add a shortcut for isMoment

Unless I'm seeing it wrong it's harder than it should be to check if an object is a moment object.
The only way I'm able to check it is if I use moment from ``import moment from 'moment'`` in my code alongside importing the service.
I could just use the moment library directly without the service but the service already has the correct timezone.
This added method to the service would be very handy.
import Ember from 'ember';
import moment from 'moment';

const { computed, Logger:logger } = Ember;

export default Ember.Service.extend({
  _timeZone: null,

  locale: null,
  defaultFormat: null,

  init() {
    this._super(...arguments);

    if (!this.get('defaultFormat')) {
      this.set('defaultFormat', 'LLLL');
    }
  },

  timeZone: computed('_timeZone', {
    get() {
      return this.get('_timeZone');
    },

    set(propertyKey, timeZone) {
      if (!moment.tz) {
        logger.warn('[ember-moment] attempted to set timezone, but moment-timezone unavailable.');
        return;
      }

      this.set('_timeZone', timeZone);

      return timeZone;
    }
  }),

  changeLocale(locale) {
    this.set('locale', locale);
  },

  changeTimeZone(timeZone) {
    this.set('timeZone', timeZone);
  },
  
  isMoment(obj) {
    return moment.isMoment(obj);
  },

  moment() {
    let time = moment(...arguments);
    const locale = this.get('locale');
    const timeZone = this.get('timeZone');

    if (locale) {
      time = time.locale(locale);
    }

    if (timeZone && time.tz) {
      time = time.tz(timeZone);
    }

    return time;
  }
});

import Ember from 'ember';
import moment from 'moment';

const { computed, Logger:logger } = Ember;

export default Ember.Service.extend({
  _timeZone: null,

  locale: null,
  defaultFormat: null,

  init() {
    this._super(...arguments);

    if (!this.get('defaultFormat')) {
      this.set('defaultFormat', 'LLLL');
    }
  },

  timeZone: computed('_timeZone', {
    get() {
      return this.get('_timeZone');
    },

    set(propertyKey, timeZone) {
      if (!moment.tz) {
        logger.warn('[ember-moment] attempted to set timezone, but moment-timezone unavailable.');
        return;
      }

      this.set('_timeZone', timeZone);

      return timeZone;
    }
  }),

  changeLocale(locale) {
    this.set('locale', locale);
  },

  changeTimeZone(timeZone) {
    this.set('timeZone', timeZone);
  },

  moment() {
    let time = moment(...arguments);
    const locale = this.get('locale');
    const timeZone = this.get('timeZone');

    if (locale) {
      time = time.locale(locale);
    }

    if (timeZone && time.tz) {
      time = time.tz(timeZone);
    }

    return time;
  }
});
