\#64806 drops the `href` part of `SamePageMessageBus` URIs. This creates a conflict, which breaks the directive explorer, between the prod Devtools (i.e. the extension) and the dev Devtools app due to the backend URIs using the same string for both prod and dev.
- Move all styles to ng-devtools/src/styles.
- Create a BrowserService that detects the browsers and adds it as a class to the body. Move global browser styles.
- Create theme mixins that incorporate the browser type into them.
- Refactor some of the affected code along with the introduced changes.
PR Close#59589
