May need to adjust scancode parsing variable names

[rnjudge]

Description Potentially revert or modify https://github.com/tern-tools/tern/commit/ce5c76305c577e089879d28c7e9e0fdeac20045e when resolution has been reached for https://github.com/nexB/scancode-toolkit/issues/2803.

The declared_license naming field is perhaps not something Tern should collect as it is currently only the extracted license statement that exists in a package manifest using the same data structure as provided upstream, so it could be a list, a string, a dict or anything. declared_license is NOT normalized by design since it is supposed to represent the upstream data and structure. Instead the license_expression (which Tern collects as part of a package licenses attribute is probably what we want since it contains the normalized license expression using ScanCode keys.

[AyanSinhaMahapatra]

See https://github.com/nexB/scancode-toolkit/issues/2803#issuecomment-1317336149