Some license test files are masking each other

The following RULE file pairs have the same generated validation test method name, hence masking each other:
- `cnri-python-1.6.1.RULE` and `cnri-python-1.6_1.RULE` have both a validation test method `cnri_python_1_6_1_rule`
- same with `proprietary-10.RULE` and `proprietary_10.RULE` with a a validation test method of `proprietary_10_rule`

See:
- https://github.com/aboutcode-org/scancode-toolkit/blob/develop/src/licensedcode/data/rules/cnri-python-1.6.1.RULE
- https://github.com/aboutcode-org/scancode-toolkit/blob/develop/src/licensedcode/data/rules/cnri-python-1.6_1.RULE
- https://github.com/aboutcode-org/scancode-toolkit/blob/develop/src/licensedcode/data/rules/proprietary-10.RULE
- https://github.com/aboutcode-org/scancode-toolkit/blob/develop/src/licensedcode/data/rules/proprietary_10.RULE

We should:
1. rename one of the rules in each pair
2. add a new test to avoid this issue in the future