[native] change color theme of the emoji keyboard based on the app theme

Summary:
This diff adds a color theme to the emoji keyboard based on the theme of the app. I tried to reuse as many of the preexisting color variables as I could; however, there were a few theme properties of the emoji keyboard where I needed to create a new color variable

Here are some docs that I used to help me implement this:
https://thewidlarzgroup.github.io/rn-emoji-keyboard/docs/api/theme

Linear Task: https://linear.app/comm/issue/ENG-3793/mobile-emoji-keyboard-darklight-mode-theme

Depends on D8309

Test Plan:
Here are the screenshots of what the emoji keyboard looks like and I spoke with @ted and got his stamp of approval

Light mode:

Dark mode:

Reviewers: atul, kamil

Reviewed By: kamil

Subscribers: ashoat, tomek, ted

Differential Revision: https://phab.comm.dev/D8310