[4.0] Fixing com_media URLs for frontend

[SharkyKZ]

Fixes #30005.

Summary of Changes

Currently media manager doesn't work in frontend if you're not logged in to backend because all URLs point to backend. This is an attempt to fix the issue.

Testing Instructions

node build.js --compile-js required.
Log out of backend.
Login to frontend.
Edit an article in frontend.
In editor click CMS Content -> Image to insert an image.

Actual result BEFORE applying this Pull Request

Doesn't work.

Expected result AFTER applying this Pull Request

Works.

Documentation Changes Required

No.

[Quy]

It is working, however, the image will not insert into the article.

[SharkyKZ]

I can't reproduce the issue. Are you getting any JS errors?

[Quy]

Sorry, never mind. I forgot to clear the browser's cache.

[Quy]

I have tested this item ✅ successfully on 2f83cd7

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[infograf768]

I have tested this item ✅ successfully on 2f83cd7

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_{This comment was created with the J!Tracker Application at issues.joomla.org/tracker/joomla-cms/30617.}

[infograf768]

RTC

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_{This comment was created with the J!Tracker Application at issues.joomla.org/tracker/joomla-cms/30617.}

[wilsonge]

Thanks!

[infograf768]

Problem editing image, see #30664
@SharkyKZ