Change search pop-out in web UI (#24305)

app/javascript/mastodon/actions/search.js

...avascript/mastodon/features/compose/components/search.jsx

...t/mastodon/features/compose/components/search_results.jsx

.../mastodon/features/compose/containers/search_container.js

...astodon/features/compose/containers/warning_container.jsx

app/javascript/mastodon/features/explore/results.jsx

app/javascript/mastodon/locales/en.json

app/javascript/mastodon/reducers/search.js

app/javascript/mastodon/utils/hashtags.js

app/javascript/styles/mastodon/components.scss