[4.0] Correcting mutilingual sampledata plugin

[infograf768]

Summary of Changes

Correcting typo introduced in #24025
Also normalizing params compared to a new Content List All Categories menu item

Testing Instructions

Install a clean 4.0 site.
When installing, also install one of the possible languages (French, German DE, Persian)
In Control panel, click the module to install the Multilingual sample data
Then in the specific language Main menu, edit the List All Categories menu item

Before patch

An error has occurred.

    0 Error decoding JSON data: Syntax error 

After patch

Issue solved

Can be tested with patchtester.

[richard67]

I have tested this item ✅ successfully on cd34ccb

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[alikon]

I have tested this item ✅ successfully on cd34ccb

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[alikon]

RTC

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[laoneo]

Thanks!