Bump lodash in /gui/public/javascripts/popper.js/packages/test-utils

Bumps [lodash](https://github.com/lodash/lodash) from 4.17.4 to 4.17.15.
- [Release notes](https://github.com/lodash/lodash/releases)
- [Commits](lodash/lodash@4.17.4...4.17.15)

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

Author: dependabot[bot]

gui/public/javascripts/popper.js/packages/test-utils/yarn.lock

@@ -120,8 +120,8 @@ js-tokens@^3.0.0:
   resolved "https://registry.yarnpkg.com/js-tokens/-/js-tokens-3.0.2.tgz#9866df395102130e38f7f996bceb65443209c25b"
 
 lodash@^4.2.0:
-  version "4.17.4"
-  resolved "https://registry.yarnpkg.com/lodash/-/lodash-4.17.4.tgz#78203a4d1c328ae1d86dca6460e369b57f4055ae"
+  version "4.17.15"
+  resolved "https://registry.yarnpkg.com/lodash/-/lodash-4.17.15.tgz#b447f6670a0455bbfeedd11392eff330ea097548"
 
 loose-envify@^1.0.0:
   version "1.3.1"