chore: fix updatePrefs not working with new object based params

[ChiragAgg5k]

What does this PR do?

• since for updatePrefs old method's first param was also an object, made the check a bit stricter to see if prefs exist in the object:

    if (paramsOrFirst && typeof paramsOrFirst === 'object' && !Array.isArray(paramsOrFirst) && 'prefs' in paramsOrFirst) {
  

  still doesnt cover the edge case where key of the preferences is also prefs... but the change is breaking 😅

• update deprecated message to be clearer with examples:

   /**
    * @deprecated Parameter-based methods will be removed in the upcoming version.
    * Please use the object based method instead for better developer experience.
    *
    * @example
    * // Old (deprecated)
    * updatePrefs<Preferences extends Models.Preferences = Models.DefaultPreferences>(prefs: Partial<Preferences>): Promise<Models.User<Preferences>>;
    *
    * // New (object based)
    * updatePrefs<Preferences extends Models.Preferences = Models.DefaultPreferences>(params: { prefs: Partial<Preferences>  }): Promise<Models.User<Preferences>>;
    */

Test Plan

Related PRs and Issues

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yes.