fix(deps): Readd fixed style import from nextcloud/dialogs

[nickvergessen]

☑️ Resolves

• Fix Fix nextcloud/dialogs usage #10854

🖌️ UI Checklist

• 🌏 Tested with Chrome, Firefox and Safari or should not be risky to browser differences
• 🖌️ Design was reviewed, approved or inspired by the design team
• ⛑️ Tests are included or not possible
• 📗 User documentation in https://github.com/nextcloud/documentation/tree/master/user_manual/talk has been updated or is not required

[ShGKme]

PR updated.

@nextcloud/dialogs requires importing styles and supposed to be used as

import { showError } from '@nextcloud/dialogs'
import '@nextcloud/dialogs/style.css'

But we use dialogs in 60+ modules. It is easy to forget import styles each time.

Importing styles once per entry point is enough to use dialogs on the entry point.

In this commit, styles are imported only in entry points were they are needed by manual check.

• Imported via common init.js
  • main: main.js
  • files-sidebar: mainFilesSidebar.js + mainFilesSidebarLoader.js
  • public-share-auth-sidebar: mainPublicShareAuthSidebar.js
  • public-share-sidebar: mainPublicShareSidebar.js
• Imported manually
  • maps: maps.js
  • deck: deck.js
  • admin-settings: mainAdminSettings.js
  • recording: mainRecording.js
• Not imported, don't use @nextcloud/dialogs:
  • dashboard: dashboard.js
  • flow: flow.js
  • collections: collections.js

This is not very reliable, because we may add a new entry point, or start to use dialogs in some existing entry point without dialogs, or stop using dialogs in some entry point.

But it's simple and clear.

Alternative solutions:

• Import everywhere with webpack config no matter if @nextcloud/dialogs are used
• Use @nextcloud/dialogs via wrapper module and forbid direct import by ESLint rule:

  // utils/nextcloudDialogs.js
  import '@nextcloud/dialogs/style.css'
  export * from '@nextcloud/dialogs'

[Antreesy]

Styles for toast messages and file pickers are loaded and referred to spreed repo.
There is another style source from server with 404, but it seems to not have an effect on Talk app

Tested for:

• main.js
• mainAdminSettings.js
• init.js (file sidebar)