MyDownloads bug fixes

[marcellamaki]

Summary

This PR generally:
Cleans up/improves reactivity on the frontend
Fixes broken remove download functionality

References

Fixes #11026
Fixes #11044

my-downloads-page.mp4

Reviewer guidance

1. Import a LOD from an existing facility
2. Import resources from that facility over the "local network"
3. Sort and filter requests
4. Remove requests - removing a single or a selection on download items should work

there will be a follow up PR on Monday that manages:

• polling for status updates on the downloads
• error handling for errors when the source device is no longer on the network
• ensure that the "download" icon is properly reactive both on the content cards and within the content renderer (still inconsistent)

Testing checklist

• Contributor has fully tested the PR manually
• If there are any front-end changes, before/after screenshots are included
• Critical user journeys are covered by Gherkin stories
• Critical and brittle code paths are covered by unit tests

PR process

• PR has the correct target branch and milestone
• PR has 'needs review' or 'work-in-progress' label
• If PR is ready for review, a reviewer has been added. (Don't use 'Assignees')
• If this is an important user-facing change, PR or related issue has a 'changelog' label
• If this includes an internal dependency change, a link to the diff is provided

Reviewer checklist

• Automated test coverage is satisfactory
• PR is fully functional
• PR has been tested for accessibility regressions
• External dependency files were updated if necessary (yarn and pip)
• Documentation is updated
• Contributor is in AUTHORS.md

[github-actions]

Build Artifacts

Asset type	Download link
PEX file	kolibri-0.16.0b1.dev0_git.100.gb71a7313.pex
Windows Installer (EXE)	kolibri-0.16.0b1.dev0+git.100.gb71a7313-unsigned.exe
Debian Package	kolibri_0.16.0b1.dev0+git.100.gb71a7313-0ubuntu1_all.deb
Mac Installer (DMG)	kolibri-0.16.0b1.dev0+git.100.gb71a7313-0.3.0.dmg
TAR file	kolibri-0.16.0b1.dev0+git.100.gb71a7313.tar.gz
WHL file	kolibri-0.16.0b1.dev0+git.100.gb71a7313-py2.py3-none-any.whl

[rtibbles]

Some things that could be cleaned up, at least one thing that looks incorrect to me.

[rtibbles]

Main feedback addressed - additional cleanup and tweaks can happen in follow up.

[rtibbles]

Test failure is due to a flaky test from another PR. Merging, will resolve elsewhere.