Chore: Remove tether and tether drop dependency in grafana/ui (#17745)

packages/grafana-ui/package.json

@@ -37,8 +37,6 @@
     "react-storybook-addon-props-combinations": "1.1.0",
     "react-transition-group": "2.6.1",
     "react-virtualized": "9.21.0",
-    "tether": "1.4.5",
-    "tether-drop": "https://github.com/torkelo/drop/tarball/master",
     "tinycolor2": "1.4.1"
   },
   "devDependencies": {
@@ -64,7 +62,6 @@
     "@types/storybook__addon-info": "4.1.1",
     "@types/storybook__addon-knobs": "4.0.4",
     "@types/storybook__react": "4.0.1",
-    "@types/tether-drop": "1.4.8",
     "@types/tinycolor2": "1.4.1",
     "awesome-typescript-loader": "5.2.1",
     "pretty-format": "24.5.0",

yarn.lock

@@ -2366,16 +2366,6 @@
   resolved "https://registry.yarnpkg.com/@types/systemjs/-/systemjs-0.20.6.tgz#79838d2b4bce9c014330efa0b4c7b9345e830a72"
   integrity sha512-p3yv9sBBJXi3noUG216BpUI7VtVBUAvBIfZNTiDROUY31YBfsFHM4DreS7XMekN8IjtX0ysvCnm6r3WnirnNeA==
 
-"@types/tether-drop@1.4.8":
-  version "1.4.8"
-  resolved "https://registry.yarnpkg.com/@types/tether-drop/-/tether-drop-1.4.8.tgz#8d64288e673259d1bc28518250b80b5ef43af0bc"
-  dependencies:
-    "@types/tether" "*"
-
-"@types/tether@*":
-  version "1.4.4"
-  resolved "https://registry.yarnpkg.com/@types/tether/-/tether-1.4.4.tgz#0fde1ccbd2f1fad74f8f465fe6227ff3b7bff634"
-
 "@types/through@*":
   version "0.0.29"
   resolved "https://registry.yarnpkg.com/@types/through/-/through-0.0.29.tgz#72943aac922e179339c651fa34a4428a4d722f93"