Chore: Set tsconfig target to ES6 (#44842)

* chore(tsconfig): update grafana/tsconfig to 1.2.0 for outputting es6

* rewrote the unsubscription part to use first().

* test: update failing tests to work with es6 output

* removed bug where we dispatch a promise instead of an array of ritch history.

Co-authored-by: Marcus Andersson <marcus.andersson@grafana.com>

packages/grafana-runtime/package.json

@@ -35,7 +35,7 @@
     "tslib": "2.3.1"
   },
   "devDependencies": {
-    "@grafana/tsconfig": "^1.0.0-rc1",
+    "@grafana/tsconfig": "^1.2.0-rc1",
     "@rollup/plugin-commonjs": "21.0.1",
     "@rollup/plugin-node-resolve": "13.1.3",
     "@testing-library/dom": "8.11.3",