[5] correct forum link

[alikon]

Pull Request for Issue #43413 .

Summary of Changes

correct forum link to 5.x https://forum.joomla.org/viewforum.php?f=834

Testing Instructions

Postinstall component administrator/index.php?option=com_postinstall

Actual result BEFORE applying this Pull Request

link to 4.x https://forum.joomla.org/viewforum.php?f=808

Expected result AFTER applying this Pull Request

correct forum link to 5.x https://forum.joomla.org/viewforum.php?f=834

Link to documentations

Please select:

• Documentation link for docs.joomla.org:

• No documentation changes for docs.joomla.org needed

• Pull Request link for manual.joomla.org:

• No documentation changes for manual.joomla.org needed

[Quy]

I have tested this item ✅ successfully on 4e4a8cb

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[viocassel]

I have tested this item ✅ successfully on 4e4a8cb

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_{This comment was created with the J!Tracker Application at issues.joomla.org/tracker/joomla-cms/43414.}

[Quy]

RTC

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[LadySolveig]

Thank you @alikon and for the tests @Quy @viocassel !