feat(layout): add alt layer support to Ergopti (@adrienm7) (#6410)

### Description

This PR updates the Ergopti layout to add the symbols of the AltGr layer

### Checks

- [ ] Adding quotes?
- [ ] 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!
- [x] Check if any open issues are related to this PR; if so, be sure to
tag them below.
- [x] Make sure the PR title follows the Conventional Commits standard.
(https://www.conventionalcommits.org for more info)
- [x] Make sure to include your GitHub username prefixed with @ inside
parentheses at the end of the PR title.

frontend/static/layouts/_list.json

@@ -2293,10 +2293,10 @@
     "keymapShowTopRow": false,
     "type": "iso",
     "keys": {
-      "row1": ["=+", "11", "22", "33", "44", "55", "66", "77", "88", "99", "0º", "€£", "%‰"],
-      "row2": ["èÈ", "yY", "oO", "wW", "bB", "fF", "gG", "hH", "cC", "xX", "zZ", "çÇ"],
-      "row3": ["aA", "iI", "eE", "uU", ".:", "vV", "sS", "nN", "tT", "rR", "qQ", "^!"],
-      "row4": ["êÊ", "éÉ", "àÀ", "jJ", ",;", "kK", "mM", "dD", "lL", "pP", "'?"],
+      "row1": ["=+}", "1111", "2222", "3333", "4444", "5555", "6666", "7777", "8888", "9999", "0º°ª", "€€£¤", "%%‰‱"],
+      "row2": ["èÈ`„", "yY@", "oOœŒ", "wWùÙ", "bB«“", "fF»”", "gG~≈", "hH#%", "cC", "xX*×", "zZ", "çÇ"],
+      "row3": ["aA<⩽", "iI>⩾", "eE{ᵉ", "uU}", ".::·", "vV|¦", "sS(—", "nN)–", "tT[", "rR[", "qQ’", "^!!¡"],
+      "row4": ["êÊ", "éÉ/÷", "àÀ\\ᵢ", "jJ\"", ",;;", "kK…", "mM&−", "dD$§", "lL=≠", "pP+±", "'??¿"],
       "row5": [" -"]
     }
   },