impr(quotes): add bulgarian quotes (@Gogo200202) (#5898)

### Description
add bulgarian quote
translations: If I win, I win for the whole nation – if I lose, I lose
only myself.
<!-- Please describe the change(s) made in your PR -->

### Checks

- [x] Adding quotes?
- [x] Make sure to include translations for the quotes in the
description (or another comment) so we can verify their content.
- [ ] Adding a language or a theme?
- [ ] If is a language, did you edit `_list.json`, `_groups.json` and
add `languages.json`?
  - [ ] If is a theme, did you add the theme.css?
- Also please add a screenshot of the theme, it would be extra awesome
if you do so!
- [ ] Check if any open issues are related to this PR; if so, be sure to
tag them below.
- [ ] Make sure the PR title follows the Conventional Commits standard.
(https://www.conventionalcommits.org for more info)
- [ ] Make sure to include your GitHub username prefixed with @ inside
parentheses at the end of the PR title.

<!-- label(optional scope): pull request title (@your_github_username)
-->

<!-- I know I know they seem boring but please do them, they help us and
you will find out it also helps you.-->

Closes #

<!-- the issue(s) your PR resolves if any (delete if that is not the
case) -->
<!-- please also reference any issues and or PRs related to your pull
request -->
<!-- Also remove it if you are not following any issues. -->

<!-- pro tip: you can mention an issue, PR, or discussion on GitHub by
referencing its hash number e.g:
[#1234](#1234) -->

<!-- pro tip: you can press . (dot or period) in the code tab of any
GitHub repo to get access to GitHub's VS Code web editor Enjoy! :) -->

frontend/static/quotes/bulgarian.json

@@ -102,6 +102,12 @@
       "source": "Емил Стоянов",
       "length": 95,
       "id": 16
+    },
+    {
+      "text": "Ако спечеля, печеля за цял народ – ако загубя, губя само мене си.",
+      "source": "Васил Левски",
+      "length": 65,
+      "id": 17
     }
   ]
 }