[4.0] Add fallback for the new media setting and fix some phpcs

[zero-24]

Pull Request for Issue #34634

Summary of Changes

Add fallback for the new media setting and fix some phpcs

Testing Instructions

Install 3.10-alpha9
Upgrade to the latest 4.0
Notice that you can not upload images in the media manager
Install a new 3.10-alpha9
Update using this update server (https://ci.joomla.org/artifacts/joomla/joomla-cms/4.0-dev/34778/downloads/45806/pr_list.xml)
Notice that the upload works

Actual result BEFORE applying this Pull Request

Media Manager Upload works

Expected result AFTER applying this Pull Request

Media Manager upload does not work when the option is not set yet.

Documentation Changes Required

none

[particthistle]

I have tested this item ✅ successfully on 733728b

Before: 4.0.0-rc5-dev (13/7/2021) was unable to upload images.

After: 4.0.0-rc5-dev+pr.34778 - able to upload images to media manager.

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[richard67]

I have tested this item ✅ successfully on 733728b

Easier test:

1. Update a current 3.10-dev or latest 3.10 nightly or 3.10-alpha9 to the latest 4.0 nightly build.
2. Try to upload a png file in media manager => fails.
3. Update now to the custom update URL built by Drone for this PR.
4. Try to upload a png file in media manager => works.

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[richard67]

RTC

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[Quy]

Thanks!