[lldb/crashlog] Fix the image_regex_uuid to skip null UUID images

This patch updates the image_regex_uuid matcher to match null-UUID
images in the plain text crashlog parser.

It updates the regex to match one or more '?' characters or the image
full path.

rdar://100904019

Differential Revision: https://reviews.llvm.org/D135482



Signed-off-by: Med Ismail Bennani <medismail.bennani@gmail.com>