Fix Loader Misallignment and Flickering

[iskipu]

Summary

This PR fixes Loader misalignment in some places, and also resolves flickering of loader in download page.

loader_align.mp4

References

Fix #11884

[github-actions]

Build Artifacts

Asset type	Download link
PEX file	kolibri-0.16.1.dev0_git.20240302044527.pex
Windows Installer (EXE)	kolibri-0.16.1.dev0+git.20240302044527-unsigned.exe
Debian Package	kolibri_0.16.1.dev0+git.20240302044527-0ubuntu1_all.deb
Mac Installer (DMG)	kolibri-0.16.1.dev0+git.20240302044527-0.4.0.dmg
Android Package (APK)	kolibri-0.16.1.dev0+git.20240302044527-0.1.0-debug.apk
TAR file	kolibri-0.16.1.dev0+git.20240302044527.tar.gz
WHL file	kolibri-0.16.1.dev0+git.20240302044527-py2.py3-none-any.whl

[LianaHarris360]

Thank you for working on this, the improvement of the icon alignment is definitely noticeable! One small issue I noticed is a console error related to setting disableDefaultTransition to string "true" instead of a Boolean value.

[iskipu]

Thanks @LianaHarris360 i overlooked it, fixed it in the new commit.

[LianaHarris360]

Everything looks good, thank you!