Bump color-string from 1.5.5 to 1.9.1 in /ui

Bumps [color-string](https://github.com/Qix-/color-string) from 1.5.5 to 1.9.1.
- [Release notes](https://github.com/Qix-/color-string/releases)
- [Changelog](https://github.com/Qix-/color-string/blob/master/CHANGELOG.md)
- [Commits](Qix-/color-string@1.5.5...1.9.1)

---
updated-dependencies:
- dependency-name: color-string
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

ui/package-lock.json

@@ -58,7 +58,7 @@
     "caniuse-lite": "^1.0.30001279",
     "classnames": "^2.3.1",
     "codemirror": "^5.65.5",
-    "color-string": "^1.5.5",
+    "color-string": "^1.9.1",
     "cron-time-generator": "^1.3.0",
     "eslint-loader": "^4.0.2",
     "glob-parent": "^5.1.2",