Avoid displaying CoachClassListPage until after data is finished loading

[LianaHarris360]

Summary

This pull request handles the brief flash of the CoachClassListPage when there's only a single class, after navigating from another plugin to a page in the Coach plugin. The page now renders and displays only after the data is fully loaded. This allows the redirection implemented in classIdParamRequiredGuard() to correctly display the CoachClassListPage only when necessary.

Correct behavior:

coachplugincorrect.mov

References

Fixes #12815

Reviewer guidance

1. Navigate to any coach page from another plugin. Inspecting the page, pressing the Network tab, and setting the network throttling to slow 4g or 3g would be helpful to see a slower transition.

[github-actions]

Build Artifacts

Asset type	Download link
PEX file	kolibri-0.18.0a0.dev0_git.162.g61918c55.pex
Windows Installer (EXE)	kolibri-0.18.0a0.dev0+git.162.g61918c55-windows-setup-unsigned.exe
Debian Package	kolibri_0.18.0a0.dev0+git.162.g61918c55-0ubuntu1_all.deb
Mac Installer (DMG)	kolibri-0.18.0a0.dev0+git.162.g61918c55.dmg
Android Package (APK)	kolibri-0.18.0a0.dev0+git.162.g61918c55-0.1.4-debug.apk
Raspberry Pi Image	kolibri-pi-image-0.18.0a0.dev0+git.162.g61918c55.zip
TAR file	kolibri-0.18.0a0.dev0+git.162.g61918c55.tar.gz
WHL file	kolibri-0.18.0a0.dev0+git.162.g61918c55-py2.py3-none-any.whl

[nucleogenesis]

I tested this locally and still see the flash.

2024-12-16.13-35-21.mp4

Does the CoachClassListPage have to be loaded at all if there is only one class? I wonder if maybe we could avoid routing to the page altogether in this case?

[LianaHarris360]

I was able to prevent loading the CoachClassListPage if there is only one class, avoiding the brief flash before the correct page is displayed. I added the check classListPageEnabled to the page, which will not display the page if there is only one class. Thanks for the suggestion @nucleogenesis

CoachClassListCorrect.mov

[AllanOXDi]

Tested it locally and works fine for me. Thanks @LianaHarris360

[nucleogenesis]

Code changes LGTM! Thanks Liana