feat(modelarmor): add Model Armor PHP and C# SDK support (#12099)

- [ ] Regenerate this pull request now.

docs(modelarmor): fixed the documentation for DetectionConfidenceLevel

PiperOrigin-RevId: 753847147

Source-Link: https://togithub.com/googleapis/googleapis/commit/4ed1e92c372c3e057fe73e04d2c82c69b9c8cb98

Source-Link: https://togithub.com/googleapis/googleapis-gen/commit/386b9402012712bc250dfdf4da8acdade502777c
Copy-Tag: eyJwIjoiLmdpdGh1Yi8uT3dsQm90LnlhbWwiLCJoIjoiMzg2Yjk0MDIwMTI3MTJiYzI1MGRmZGY0ZGE4YWNkYWRlNTAyNzc3YyJ9

Author: gcf-owl-bot[bot]