Removed null check for GetReviewsRequestValidator

[annstriganova]

1. Task's name:

Allow empty list with rating values

2. Developer's full name:

Anna Striganova

3. Changes:

• removed null check for ratings list from validator

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Files with missing lines	Coverage Δ	Complexity Δ
...e/review/validator/GetReviewsRequestValidator.java	47.61% <ø> (-6.55%)	3.00 <0.00> (-1.00)

... and 2 files with indirect coverage changes