edk2_pr_eval: Policy 5: allow dsc parse failures (#617)

Given that PR eval runs before dependencies are downloaded, there will
be cirumstances where files used in the dsc are not present. This can
be tollerated by setting NoFailMode, which just results in the parser
moving onto the next line when the parsing fails.

edk2toolext/invocables/edk2_pr_eval.py

@@ -324,6 +324,7 @@ def get_packages_to_build(self, possible_packages: list) -> dict:
                     continue
 
                 dsc_parser = DscParser()
+                dsc_parser.SetNoFailMode()
                 dsc_parser.SetEdk2Path(self.edk2_path_obj).SetInputVars(defines)
                 dsc_parser.ParseFile(dsc)