emoji-picker: implement text-labeled subcategory bar for emoticons.

* render emoji-based or text-based subcategory bar conditionally,
depending on the selected category to match Figma mock (text group
button for emoticons, icon group button for emoji).

* hide chevrons and small blue indicator for text-labelled
subcategory bar temporarily.

* add new subcategory data for emoticons. It is used for rendering group
tabs.

Behavior note:
* Click at emoticon category button, the subcategory bar with TEXT
buttons is displayed.
* Click at emoji category button, the subcategory bar with EMOJI buttons
is displayed.
* Click at any tab at emoticon tab, it is expected there is neither any
update nor scrolling behavior.

* 1. new text-based: https://screenshot.googleplex.com/8jjPg3p3A5GdiEh
* 2. existing icon-based: https://screenshot.googleplex.com/Bayb38kZTNVXK2B

Screenshots: 
Bug: b:212478355
Change-Id: I611ee2334672156e732f0562f281c6d245476f61
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3358164
Reviewed-by: Keith Lee <keithlee@chromium.org>
Reviewed-by: My Nguyen <myy@chromium.org>
Commit-Queue: Chuong Ho <hdchuong@google.com>
Cr-Commit-Position: refs/heads/main@{#954567}