Feature matrix issues

[ireneisdoomed]

Describe the bug List of bugs identified by @addramir that we need to investigate:

• [ ] Unexpected nulls for confidence, proteinGeneCount, isProteinCoding
• [x] Rows with null geneId
• [x] Rows with null studyLocusId
• [x] Some rows have negative distanceTssMean values

[ireneisdoomed]

Note: all rows without a geneId have only confidence annotation, so the bug must be in CredibleSetConfidenceFeature

For the rows with null studyLocusId, there is no other annotation whatsoever