Range queries for undefined start or end bytes fails due to regex

### Problem:

Range queries without a start or end byte range fail due to https://github.com/aws/amazon-s3-encryption-client-java/blob/main/src/main/java/software/amazon/encryption/s3/legacy/internal/RangedGetUtils.java#L21.

### Solution:

Adjust the regex to allow for start or end byte range to not exist.

Start by reading src/main/java/software/amazon/encryption/s3/legacy/internal/RangedGetUtils.java at line 21 and trace how range queries are parsed. Reproduce requests with an undefined start or end byte, then verify both forms are accepted without breaking fully specified ranges.

Written by the indexing model from the issue text.