Editor: limit uploads to supported mime types

[adamsilverstein]

Trac ticket: https://core.trac.wordpress.org/ticket/61167

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[adamsilverstein]

Previously this was #6531, in this PR I expanded it to include checks for all mime types, so this now covers heic uploads as well.

[github-actions]

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[apermo]

Technically flawless, I suggested a minor doc change to be more precise.

[adamsilverstein]

The issue with this approach is that it prevents users from uploading mp3s or other non-image types. Instead, we should add similar explicit checks for file type support for webp, avif and heic, the same way we do for media -

wordpress-develop/src/wp-includes/media.php

Lines 4352 to 4365 in a48e180

	// Check if WebP images can be edited.
	if ( ! wp_image_editor_supports( array( 'mime_type' => 'image/webp' ) ) ) {
	$defaults['webp_upload_error'] = true;
	}
	// Check if AVIF images can be edited.
	if ( ! wp_image_editor_supports( array( 'mime_type' => 'image/avif' ) ) ) {
	$defaults['avif_upload_error'] = true;
	}
	// Check if HEIC images can be edited.
	if ( ! wp_image_editor_supports( array( 'mime_type' => 'image/heic' ) ) ) {
	$defaults['heic_upload_error'] = true;
	}