This fixes the bug where on hovering / selecting an emoji picker search
results emoji, invariably its canonical name would show / be used, which
is not always the same as the matching alias. For example, searching for
"swe" would show the "sweeping" emoji, but its canonical name is "broom"
which can be a confusing search result for "swe".
This commit tries to improve the CSS related to the emoji picker by
restructuring relevant parts of `reactions.css` and `dark_theme.css`.
Via this commit, the redundant classes -- "reaction", "status-emoji",
"composition" are also removed from `emoji_popover_emoji.hbs`.
If needed, specific styling -- according to the type of emoji picker,
can now be applied using the `data-emoji-destination` attribute of the
`.emoji-picker-popover`.
N-Shar-ma
Sayam Samal
Aman Agrawal