Use the right mime type in the the media field

[dgrammatiko]

Pull Request for Issue #38333 .

Summary of Changes

The preview might get the wrong mime type in some cases.

Testing Instructions

• Edit the file administrator/components/com_content/forms/article.xml and add types="images,audios,videos,documents" after https://github.com/joomla/joomla-cms/blob/7cf5e1228db337881d7678ad1c71915d5c885150/administrator/components/com_content/forms/article.xml#L752
• Try to upload and select different type of media, especially video, audio and document (eg, mp3, mp4, mov, pdf, doc, docx, etc)

Actual result BEFORE applying this Pull Request

No preview in some cases

Expected result AFTER applying this Pull Request

Preview is ok

Documentation Changes Required

No

[crystalenka]

I have tested this item :white_check_mark: successfully on abd4aca766a4e5ac61b39d8776a90d669ee9472f

Thank you!!

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[viocassel]

I have tested this item :white_check_mark: successfully on abd4aca766a4e5ac61b39d8776a90d669ee9472f

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[alikon]

RTC

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[wilsonge]

Thanks!