chore(demo): fix re-creating main portal twice

[vladimirpotekhin]

before:

1. main portal creating twice when navigating to somewhere except landing-page route

2. main-portal unexpected creating on landing-page route

[lumberjack-bot]

Pull request was closed ✔️

All saved screenshots (for current PR) were deleted 🗑️

[github-actions]

Visit the preview URL for this PR (updated for commit 43fef93):

https://taiga-previews--pr9130-fix-doc-su2pw627.web.app

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[bundlemon]

BundleMon

Files updated (2)

Status	Path	Size	Limits
✅	demo/browser/runtime.(hash).js	42.32KB (-317B -0.73%)	+10%
✅	demo/browser/main.(hash).js	287.27KB (-591B -0.2%)	+10%

Unchanged files (3)

Status	Path	Size	Limits
✅	demo/browser/vendor.(hash).js	247.15KB	+10%
✅	demo/browser/styles.(hash).css	16.18KB	+10%
✅	demo/browser/polyfills.(hash).js	11.2KB	+10%

Total files change -908B -0.15%

Groups updated (1)

Status	Path	Size	Limits
✅	demo/browser/*..js	7.05MB (-73.19KB -1%)	-

Final result: ✅

View report in BundleMon website ➡️

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Current branch size history | Target branch size history