feat: add assembling status to UploadPicker

[skjnldsv]

@Koc here is my take on this.
I think adding some text to the right isn't the right approach.
Now we make sure we don't have any ongoing upload that are NOT assembling
If all is left is assembling tasks, we show the status.

• Assembling status uploader fix
• Assembling status vue component feat
• Cypress tests

Closes #1458

[codecov]

Bundle Report

Changes will increase total bundle size by 1.33kB (0.17%) ⬆️. This is within the configured threshold ✅

Detailed changes

Bundle name	Size	Change
@nextcloud/upload-esm	396.52kB	666 bytes (0.17%) ⬆️
@nextcloud/upload-cjs	399.88kB	666 bytes (0.17%) ⬆️

[Koc]

@skjnldsv Awesome! But it still not works for me. Reproducer:

1. set max chunk size to 40 Mb
2. upload 2 files in parallel: 35 Mb (smaller than chunk to have regular upload) and 150 Mb (few times bigger than chunk to have chunked upload)

Expected: Progressbar shows upload progress and assembling status until all files are not uploaded and assembled
Actual: Progressbar hidden once 1st file uploaded. So, assembling status not shown.

nextcloud-upload-2024-12-19_10.09.23.mp4

[skjnldsv]

Will add tests and fix that use case, nice catch! :)