Migrating other 2 files from javascript to typescript (#29435)

* feat: Add initial store configuration for webapp channels

* refactor: Convert store/index.js to TypeScript with type definitions

* test: Add initial test file for store index

* refactor: Convert index.test.js to TypeScript with type annotations

* Removing old files

* Applying linter fixes

* Fixing some of the types errors

* fix: Type mock implementation of getState in global_actions.test.ts

* test: Add missing GlobalState import in global_actions.test.ts

* fix: Resolve TypeScript mock implementation error in global_actions.test.ts

* Some fixes

* Address CI problems

* Installing zen-observable types

* Addressing PR review comment

* Addressing PR review comment

* Addressing PR review comment

* Addressing PR review comment

* Addressing PR review comment

* Simpliying things

* Fixing CI

* Fixing types

webapp/package-lock.json

@@ -193,6 +193,7 @@
         "@types/shallow-equals": "1.0.3",
         "@types/styled-components": "5.1.32",
         "@types/tinycolor2": "1.4.6",
+        "@types/zen-observable": "0.8.7",
         "copy-webpack-plugin": "11.0.0",
         "emoji-datasource": "6.1.1",
         "emoji-datasource-apple": "6.1.1",
@@ -7310,6 +7311,12 @@
       "integrity": "sha512-I4q9QU9MQv4oEOz4tAHJtNz1cwuLxn2F3xcc2iV5WdqLPpUnj30aUuxt1mAxYTG+oe8CZMV/+6rU4S4gRDzqtQ==",
       "dev": true
     },
+    "node_modules/@types/zen-observable": {
+      "version": "0.8.7",
+      "resolved": "https://registry.npmjs.org/@types/zen-observable/-/zen-observable-0.8.7.tgz",
+      "integrity": "sha512-LKzNTjj+2j09wAo/vvVjzgw5qckJJzhdGgWHW7j69QIGdq/KnZrMAMIHQiWGl3Ccflh5/CudBAntTPYdprPltA==",
+      "dev": true
+    },
     "node_modules/@typescript-eslint/eslint-plugin": {
       "version": "7.18.0",
       "resolved": "https://registry.npmjs.org/@typescript-eslint/eslint-plugin/-/eslint-plugin-7.18.0.tgz",