fix(chat): focus submit on upload attachments without caption

[ShGKme]

☑️ Resolves

• Fix Press Enter on Send Image confirmation dismiss operation talk-desktop#651
• Regression of feat(NewMessageUploadEditor) - caption to file share #10730 for old servers:
  • When captions aren't supported submit button should be focus as it was before adding captions
  • Otherwise it is focused on "Close" button and Enter results in dismissing sending files
• Removed optional chaining ?. to not miss error here
• Note, getContainerId did not returned actual promise from nextTick. It word because of await just as await Promise.resolve() but it is not guaranteed

🖌️ UI Checklist

🖼️ Screenshots / Screencasts

🏚️ Before	🏡 After

🚧 Tasks

• Focus submitButton if there is no input

🏁 Checklist

• 🌏 Tested with Chrome, Firefox and Safari or should not be risky to browser differences
• 🖥️ Tested with Desktop client or should not be risky for it
• 🖌️ 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

[DorraJaouad]

Tested ✅

[Antreesy]

LGTM

[ShGKme]

/backport to stable29

[ShGKme]

/backport to stable28