OSV API exposes syntactically incorrect CVSSv4 scores

**Describe the bug**
A number of OSV records from multiple ecosystems provide a CVSSv4 vector with a trailing slash which is not valid syntax per the CVSSv4 [schema](https://www.first.org/cvss/cvss-v4.0.json) and any schema-compliant parsing library will trip up when processing such CVSSv4 vectors.

Some examples:
https://api.osv.dev/v1/vulns/GHSA-g357-x5c3-c72p
https://api.osv.dev/v1/vulns/GHSA-9p7c-v5x3-rfx8
https://api.osv.dev/v1/vulns/GHSA-78fc-9688-w8xw

**To Reproduce**
Steps to reproduce the behaviour:
1. Go to any of the above links
2. Copy the CVSSv4 vector
3. Pass it to any schema-compliant CVSS parsing library
4. Library will raise an error

**Expected behaviour**
Error is not raised, CVSSv4 vector complies with the schema.

**Screenshots**
N/A

**Additional context**
N/A

Start with the API responses for GHSA-g357-x5c3-c72p, GHSA-9p7c-v5x3-rfx8, and GHSA-78fc-9688-w8xw, then trace where their CVSSv4 vectors are stored or serialized. Compare the vectors with the CVSSv4 schema and verify them with a schema-compliant parsing library. Done means the affected API responses contain syntactically valid vectors without the trailing slash.

Written by the indexing model from the issue text.