Support strength overrides in `derivde_onco_evidence_attributes`

### Feature description

Allow `derive_onco_evidence_attributes` to accept an optional strength override. The helper would derive the evidence outcome and method from the base criterion, while deriving the score from the applied strength.

### Use case

CIViC may apply an oncogenicity criterion at a modified strength, such as OS2 at moderate strength. This should produce evidence outcome OS2, strength moderate, and score 2, rather than the default strong score of 4.

### Proposed solution

_No response_

### Alternatives considered

_No response_

### Implementation details

_No response_

### Potential Impact

_No response_

### Additional context

_No response_

### Contribution

Yes, I can create a PR for this feature.