update coach routing

[thanksameeelian]

Summary

this PR updates routing in Coach, making it more parallel to Facility in terms of its behavior upon subtopic selection in the sidenav.

previously, if a user was working elsewhere in kolibri and selected a Coach subtopic from the sidenav, we'd only retain & apply that subtopic information if they had a single facility holding single class. otherwise, they'd be redirected to All Facilities or All Classes as appropriate and, once making the necessary selection, would be redirected to the class they wanted, but always to the home page regardless of their initially chosen subtopic.

with the changes introduced here, now if a user selects a subtopic in the sidenav, that subtopic information will persist within the url as the user selects a facility and/or specific class, and once class selection is made the user is redirected to that selected subtopic, rather than the home page by default.

References

fixes #10650
fixes #10855

Reviewer guidance

there are four cases to be considered:

1. multi-facility user, in a facility with one class
2. multi-facility user, in a facility with multiple classes
3. single facility user, in a facility with one class
4. single facility user, in a facility with multiple classes

for each case,

• from another plugin in kolibri, select a Coach subtopic - Plan or Reports will show the changed behavior
• navigation should behave as normal for the case you are testing - a redirect to "All facilities" and/or "All classes" as needed to winnow down class selection
• the subtopic initially selected should persist within the current page's url & also be included in the facility- or class-specific links on the "All facilities" and "All classes" pages
• once class selection is made, user should be redirected to the subtopic initially selected (rather than "Class home," as was previously always the case)

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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-0.16.0b5.dev0_git.120.g1799566e.pex
Windows Installer (EXE)	kolibri-0.16.0b5.dev0+git.120.g1799566e-unsigned.exe
Debian Package	kolibri_0.16.0b5.dev0+git.120.g1799566e-0ubuntu1_all.deb
Mac Installer (DMG)	kolibri-0.16.0b5.dev0+git.120.g1799566e-0.3.0.dmg
Android Package (APK)	kolibri-0.16.0b5.dev0+git.120.g1799566e-0.1.0-debug.apk
TAR file	kolibri-0.16.0b5.dev0+git.120.g1799566e.tar.gz
WHL file	kolibri-0.16.0b5.dev0+git.120.g1799566e-py2.py3-none-any.whl

[rtibbles]

Makes sense so far - one question about the non-multi-facility case though!

[rtibbles]

Very nearly there - just one more thing.

[rtibbles]

All changes make sense, and manual testing checks out.

[rtibbles]

@radinamatic I had manually confirmed these fixes, so have merged, but feel free to check my working!

[pcenov]

Thanks @thanksameeelian I've also manually confirmed the fixes here and was able to identify just a couple of minor issues which I've reported separately here #11253