Update dependency webpack-merge to v5.10.0 (mastodon#27420)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

yarn.lock

@@ -6191,6 +6191,11 @@ flat-cache@^3.0.4:
     keyv "^4.5.3"
     rimraf "^3.0.2"
 
+flat@^5.0.2:
+  version "5.0.2"
+  resolved "https://registry.yarnpkg.com/flat/-/flat-5.0.2.tgz#8ca6fe332069ffa9d324c327198c598259ceb241"
+  integrity sha512-b6suED+5/3rTpUBdG1gupIl8MPFCAMA0QXwmljLhvCUKcUvdE4gWky9zpuGCcXHOsz4J9wPGNWq6OKpmIzz3hQ==
+
 flatted@^3.2.9:
   version "3.2.9"
   resolved "https://registry.yarnpkg.com/flatted/-/flatted-3.2.9.tgz#7eb4c67ca1ba34232ca9d2d93e9886e611ad7daf"
@@ -11784,6 +11789,7 @@ stringz@^2.1.0:
     char-regex "^1.0.2"
 
 "strip-ansi-cjs@npm:strip-ansi@^6.0.1", strip-ansi@^6.0.0, strip-ansi@^6.0.1:
+  name strip-ansi-cjs
   version "6.0.1"
   resolved "https://registry.yarnpkg.com/strip-ansi/-/strip-ansi-6.0.1.tgz#9e26c63d30f53443e9489495b2105d37b67a85d9"
   integrity sha512-Y38VPSHcqkFrCpFnQ9vuSXmquuv5oXOKpGeT6aGrr3o3Gc9AlVa6JBfUSOCnbxGGZF+/0ooI7KrPuUSztUdU5A==
@@ -12912,11 +12918,12 @@ webpack-log@^2.0.0:
     uuid "^3.3.2"
 
 webpack-merge@^5.9.0:
-  version "5.9.0"
-  resolved "https://registry.yarnpkg.com/webpack-merge/-/webpack-merge-5.9.0.tgz#dc160a1c4cf512ceca515cc231669e9ddb133826"
-  integrity sha512-6NbRQw4+Sy50vYNTw7EyOn41OZItPiXB8GNv3INSoe3PSFaHJEz3SHTrYVaRm2LilNGnFUzh0FAwqPEmU/CwDg==
+  version "5.10.0"
+  resolved "https://registry.yarnpkg.com/webpack-merge/-/webpack-merge-5.10.0.tgz#a3ad5d773241e9c682803abf628d4cd62b8a4177"
+  integrity sha512-+4zXKdx7UnO+1jaN4l2lHVD+mFvnlZQP/6ljaJVb4SZiwIKeUnrT5l0gkT8z+n4hKpC+jpOv6O9R+gLtag7pSA==
   dependencies:
     clone-deep "^4.0.1"
+    flat "^5.0.2"
     wildcard "^2.0.0"
 
 webpack-sources@^1.0, webpack-sources@^1.1.0, webpack-sources@^1.4.1, webpack-sources@^1.4.3: