Bump xterm from 3.14.5 to 4.9.0 in /ui

Bumps [xterm](https://github.com/xtermjs/xterm.js) from 3.14.5 to 4.9.0.
- [Release notes](https://github.com/xtermjs/xterm.js/releases)
- [Commits](xtermjs/xterm.js@3.14.5...4.9.0)

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

ui/package.json

@@ -21,7 +21,7 @@
         "rxjs-compat": "^6.5.4",
         "rxjs-hooks": "^0.6.2",
         "styled-components": "^5.2.0",
-        "xterm": "^3.14.5"
+        "xterm": "^4.9.0"
     },
     "scripts": {
         "start": "react-scripts start",

ui/yarn.lock

@@ -12762,10 +12762,10 @@ xtend@^4.0.0, xtend@~4.0.1:
   resolved "https://registry.yarnpkg.com/xtend/-/xtend-4.0.1.tgz#a5c6d532be656e23db820efb943a1f04998d63af"
   integrity sha1-pcbVMr5lbiPbgg77lDofBJmNY68=
 
-xterm@^3.14.5:
-  version "3.14.5"
-  resolved "https://registry.yarnpkg.com/xterm/-/xterm-3.14.5.tgz#c9d14e48be6873aa46fb429f22f2165557fd2dea"
-  integrity sha512-DVmQ8jlEtL+WbBKUZuMxHMBgK/yeIZwkXB81bH+MGaKKnJGYwA+770hzhXPfwEIokK9On9YIFPRleVp/5G7z9g==
+xterm@^4.9.0:
+  version "4.9.0"
+  resolved "https://registry.yarnpkg.com/xterm/-/xterm-4.9.0.tgz#7a4c097a433d565339b5533b468bbc60c6c87969"
+  integrity sha512-wGfqufmioctKr8VkbRuZbVDfjlXWGZZ1PWHy1yqqpGT3Nm6yaJx8lxDbSEBANtgaiVPTcKSp97sxOy5IlpqYfw==
 
 "y18n@^3.2.1 || ^4.0.0", y18n@^4.0.0:
   version "4.0.0"