Bump @fortawesome/fontawesome-free from 5.15.3 to 5.15.4 in /app

Bumps [@fortawesome/fontawesome-free](https://github.com/FortAwesome/Font-Awesome) from 5.15.3 to 5.15.4.
- [Release notes](https://github.com/FortAwesome/Font-Awesome/releases)
- [Changelog](https://github.com/FortAwesome/Font-Awesome/blob/master/CHANGELOG.md)
- [Commits](https://github.com/FortAwesome/Font-Awesome/compare/5.15.3...5.15.4)

---
updated-dependencies:
- dependency-name: "@fortawesome/fontawesome-free"
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>

app/package.json

@@ -57,7 +57,7 @@
     ],
     "license": "GPL-3.0",
     "dependencies": {
-        "@fortawesome/fontawesome-free": "^5.15.3",
+        "@fortawesome/fontawesome-free": "^5.15.4",
         "@syuilo/aiscript": "^0.11.1",
         "electron-dl": "^3.2.1",
         "itunes-nowplaying-mac": "https://github.com/cutls/itunes-nowplaying-mac/releases/download/v0.4.0/itunes-nowplaying-mac-0.4.0.tgz",

app/yarn.lock

@@ -84,10 +84,10 @@
     minimatch "^3.0.4"
     strip-json-comments "^3.1.1"
 
-"@fortawesome/fontawesome-free@^5.15.3":
-  version "5.15.3"
-  resolved "https://registry.yarnpkg.com/@fortawesome/fontawesome-free/-/fontawesome-free-5.15.3.tgz#c36ffa64a2a239bf948541a97b6ae8d729e09a9a"
-  integrity sha512-rFnSUN/QOtnOAgqFRooTA3H57JLDm0QEG/jPdk+tLQNL/eWd+Aok8g3qCI+Q1xuDPWpGW/i9JySpJVsq8Q0s9w==
+"@fortawesome/fontawesome-free@^5.15.4":
+  version "5.15.4"
+  resolved "https://registry.yarnpkg.com/@fortawesome/fontawesome-free/-/fontawesome-free-5.15.4.tgz#ecda5712b61ac852c760d8b3c79c96adca5554e5"
+  integrity sha512-eYm8vijH/hpzr/6/1CJ/V/Eb1xQFW2nnUKArb3z+yUWv7HTwj6M7SP957oMjfZjAHU6qpoNc2wQvIxBLWYa/Jg==
 
 "@jimp/bmp@^0.16.1":
   version "0.16.1"