Avoid crashing on invalid art box:
Avoid crashing on invalid art box:

java.lang.ArrayIndexOutOfBoundsException: 0
	at org.sejda.sambox.pdmodel.common.PDRectangle.(PDRectangle.java:129)
	at org.sejda.sambox.pdmodel.PDPage.getArtBox(PDPage.java:471)

torakiki/sambox,torakiki/sambox