Bump tinymce from 5.10.8 to 5.10.9 in /frontend (#1592)

Bumps [tinymce](https://github.com/tinymce/tinymce/tree/HEAD/modules/tinymce) from 5.10.8 to 5.10.9.
- [Changelog](https://github.com/tinymce/tinymce/blob/5.10.9/modules/tinymce/CHANGELOG.md)
- [Commits](https://github.com/tinymce/tinymce/commits/5.10.9/modules/tinymce)

---
updated-dependencies:
- dependency-name: tinymce
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

frontend/package.json

@@ -19,7 +19,7 @@
     "indent.js": "^0.3.5",
     "qs": "^6.10.1",
     "textversionjs": "^1.1.3",
-    "tinymce": "^5.10.8",
+    "tinymce": "^5.10.9",
     "turndown": "^7.0.0",
     "vue": "^2.6.12",
     "vue-i18n": "^8.22.2",

frontend/yarn.lock

@@ -7169,10 +7169,10 @@ thunky@^1.0.2:
   resolved "https://registry.yarnpkg.com/thunky/-/thunky-1.1.0.tgz#5abaf714a9405db0504732bbccd2cedd9ef9537d"
   integrity sha512-eHY7nBftgThBqOyHGVN+l8gF0BucP09fMo0oO/Lb0w1OF80dJv+lDVpXG60WMQvkcxAkNybKsrEIE3ZtKGmPrA==
 
-tinymce@^5.10.8:
-  version "5.10.8"
-  resolved "https://registry.yarnpkg.com/tinymce/-/tinymce-5.10.8.tgz#c85758fa3cca2cbb4b14dd037a0b315b6462c50e"
-  integrity sha512-iyoo3VGMAJhLMDdblAefKvYgBRk9kQi58GTwAmoieqsyggGsKZWlQl/YY6nTILFHUCA1FhYu0HdmM5YYjs17UQ==
+tinymce@^5.10.9:
+  version "5.10.9"
+  resolved "https://registry.yarnpkg.com/tinymce/-/tinymce-5.10.9.tgz#1dfacb3231c71a688d90ff44a0b3f2e91b3b9edf"
+  integrity sha512-5bkrors87X9LhYX2xq8GgPHrIgJYHl87YNs+kBcjQ5I3CiUgzo/vFcGvT3MZQ9QHsEeYMhYO6a5CLGGffR8hMg==
 
 tmp@~0.2.1:
   version "0.2.1"