Remove unused ComponentStore (#1023)

This was introduced in #96, but never used. I suspect the `import store
from "./app/store"` statement in `src/web-component.js` was intended to
import it, but it used the wrong filename.

`ComponentStore` was later effectively replaced by `WebComponentStore`
in #728.

Author: floehopper

CHANGELOG.md

@@ -27,6 +27,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 - Add e2e spec for project remix behaviour in web component (#1020)
 - Fix initial value of `user` in `WebComponentLoader` (#1021)
 - Make `authKey` in e2e web component spec more realistic (#1022)
+- Remove unused `ComponentStore` (#1023)
 
 ## [0.23.0] - 2024-05-09