build(deps): bump mobx from 5.5.0 to 5.5.1 in /ui

Bumps [mobx](https://github.com/mobxjs/mobx) from 5.5.0 to 5.5.1.
- [Release notes](https://github.com/mobxjs/mobx/releases)
- [Changelog](https://github.com/mobxjs/mobx/blob/master/CHANGELOG.md)
- [Commits](https://github.com/mobxjs/mobx/compare/5.5.0...5.5.1)

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

ui/package.json

@@ -20,7 +20,7 @@
     "lodash.debounce": "4.0.8",
     "lodash.throttle": "4.1.1",
     "lodash.uniqueid": "4.0.1",
-    "mobx": "5.5.0",
+    "mobx": "5.5.1",
     "mobx-react": "5.3.1",
     "mobx-stored": "1.0.2",
     "moment": "2.22.2",

ui/yarn.lock

@@ -7227,10 +7227,10 @@ mobx-stored@1.0.2:
     lodash.merge "^4.6.1"
     traverse "^0.6.6"
 
-mobx@5.5.0:
-  version "5.5.0"
-  resolved "https://registry.yarnpkg.com/mobx/-/mobx-5.5.0.tgz#a29f6a7526eed28edcd3f0e921a1edaa8bb22575"
-  integrity sha512-rD0Hsv9XtjS6axavvPX/XzWTeICRiH3bLR1L+MrJ7HOlx1hmSdWNzu8rQQ+1IkTiyJechRyGzs2tUgLRmEofJg==
+mobx@5.5.1:
+  version "5.5.1"
+  resolved "https://registry.yarnpkg.com/mobx/-/mobx-5.5.1.tgz#cd006b46085f6e3a6c96b183583d2ee907d37525"
+  integrity sha512-mymrvbAFIMCP5k9ylspuXPy7jeEAA8ILVRziqsLmpoGIfEJc5I4YQBLF3aKJnnqtCINJPCWEijKidpsuL6TfYw==
 
 moment@2.22.2:
   version "2.22.2"