EXT-7593 FIXED Added passing focus to the selected outfit tab when My Outfits tab is open.

- Removed "tab_stop" from outfit tabs to prevent passing focus to a tab chosen by default from LLUICtrl::focusFirstItem(). Besides the order of passing focus between outfit tabs by pressing "Tab" was undetermined.
- Had to remove const from the return of LLAccordionCtrl::getSelectedTab() to use the returned pointer for setting focus.

Reviewed by Neal Orman at https://codereview.productengine.com/secondlife/r/846/.

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branch : product-engine