[4.x] Tinmyce image decorative [a11y]

[brianteeman]

This PR enables the native tinymce feature to mark an image as decorative. This continues the work started in #31318 and #31323

Background

To read why this change is very important see #31318

Testing Part 1

Testing is really easy. No npm, js or css involved.
Merge the pull request and then use the tinmyce image button to add an image

The new options is highlighted here

Testing Part 2

Please test three scenarios

1. Image Description (Alt Text) = Empty
   Images is decorative = unchecked

2. Image Description (Alt Text) = "some description"
   Images is decorative = unchecked

3. Image Description (Alt Text) = Empty
   Images is decorative = checked

The expected behaviour for each of these tests is

1.<img src="filename.jpg" width="xx" height="xx" />
2. <img src="filename.jpg" alt="some description" width="xx" height="xx" />
3. <img role="presentation" src="filename.jpg" alt width="xx" height="xx" />
3. <img role="presentation" src="filename.jpg" alt="" width="xx" height="xx" />

PLEASE do not comment on what you think the code does but apply the PR and test it. Getting very tired of people blocking PR with their comments without actually testing the code.

Bonus

I have grouped the three image options together in the code.

cc @carcam

[pabloarias]

I have tested this item ✅ successfully on a7eace8

I've tested it successfully with Joomla 4 beta 6 daily build. This is the result:

1. <img src="images/joomla_black.png" width="225" height="50" />
2. <img src="images/joomla_black.png" alt="some description" width="225" height="50" />
3. <img role="presentation" src="images/joomla_black.png" alt="" width="225" height="50" />

Thank you!

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[maikol-ortigueira]

I have tested this item ✅ successfully on a7eace8

I have tested this item and it works perfectly.
Thank you.

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[alikon]

RTC

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[chmst]

Thanks!

[brianteeman]

Thanks