[FIX] Custom emojis to override default

[aKn1ghtOut]

Checklist

• I have read the Contributing Guide
• I have signed the CLA
• Lint and unit tests pass locally with my changes
• I have added tests that prove my fix is effective or that my feature works (if applicable)
• I have added necessary documentation (if applicable)
• Any dependent changes have been merged and published in downstream modules

Proposed changes (including videos or screenshots)

Due to the sequence of the imports and how the emojiRenderer prioritizes lists, the custom emojis could not override the emojione emojis. Making two small changes fixed the issue.

With the custom emoji for :facepalm: added, you can check out the result below:

Before

After

Issue(s)

Closes #15973

Steps to test or reproduce

1. Add a custom emoji with the name or alias same as an existing emoji.
2. Use the emoji. [ Custom emojis can not override default emojis right now ]

Further comments

All changes are non-breaking