Media: fix potentially failing Imagick PDF alpha channel test.

Only test PDF alpha functionality when supported by the server.

Props: adamsilverstein, swissspidy, antpb, sippis.
Fixes #60798.



git-svn-id: https://develop.svn.wordpress.org/trunk@60030 602fd350-edb4-49c9-b593-d223f7449a82

Author: adamsilverstein

tests/phpunit/tests/image/editorImagick.php

@@ -656,6 +656,11 @@ public function test_remove_pdf_alpha_channel_should_remove_the_alpha_channel_in
 			$this->markTestSkipped( 'Rendering PDFs is not supported on this system.' );
 		}
 
+		$version = Imagick::getVersion();
+		if ( $version['versionNumber'] < 0x675 ) {
+			$this->markTestSkipped( 'The version of ImageMagick does not support removing alpha channels from PDFs.' );
+		}
+
 		$test_file     = DIR_TESTDATA . '/images/test-alpha.pdf';
 		$attachment_id = $this->factory->attachment->create_upload_object( $test_file );
 		$this->assertNotEmpty( $attachment_id, 'The attachment was not created before testing.' );