Fix invalid SPDX expressions for license exceptions to use WITH operator

[dikshaa2909]

Fixes #4623

Description

ScanCode was generating invalid SPDX license expressions when combining licenses with their exceptions. According to SPDX specification, exceptions must be combined with licenses using the WITH operator, not AND.

Before:

"detected_license_expression_spdx": "GPL-3.0-only AND GCC-exception-3.1"

After:

"detected_license_expression_spdx": "GPL-3.0-only WITH GCC-exception-3.1"

Changes

• Added combine_expressions_with_exception_handling() function to detect when a license is paired with an exception and combine them using WITH instead of AND
• Modified get_detected_license_expression() to use the new function
• Added test case test_gpl_with_gcc_exception_uses_with_operator() to verify the fix

Testing

• Tested with the original reproduction case from issue Invalid SPDX expressions for license exceptions #4623
• All existing exception-related tests pass (6/6)
• All detection tests pass (38/38)
• New test case added and passing

Tasks

• Reviewed contribution guidelines
• PR is descriptively titled and links the original issue above
• Tests pass
• Commits are in uniquely-named feature branch and has no merge conflicts
• Updated documentation pages (if applicable)
• Updated CHANGELOG.rst (if applicable)