Add the ability to parse CWE/cwe-{number} format for external identifier

Right now what we are using in security training url finder only supports number but after this fix this will support both "89" and "CWE-89" (cwe-89) format so that we can derive mapping key for external call for provider properly.

pry(main)> "cwe-24".split('-').last
=> "24"
pry(main)> "24".split('-').last
=> "24"

Will work for both format:

Related to #357008