GF-60193: [RC.6 Sanity check] Lose focus when last focused control is not spot-table on container

This problem is reported on Sanity check of moonstone rc.6 and
introduced on bug fix for GF-58554.

There is a call to static function of spotlight from decorator.
And this makes losing focus.

Need to fix oChild = this.getFirstChild(oChild); to oChild =
enyo.Spotlight.getFirstChild(oChild);

DCO-1.1-Signed-Off-By: Kunmyon Choi <kunmyon.choi@lge.com>