Update openvino requirement in /docker/main

Updates the requirements on [openvino](https://github.com/openvinotoolkit/openvino) to permit the latest version.
- [Release notes](https://github.com/openvinotoolkit/openvino/releases)
- [Changelog](https://github.com/openvinotoolkit/openvino/blob/master/docs/RELEASE.MD)
- [Commits](https://github.com/openvinotoolkit/openvino/commits/2026.4.1)

---
updated-dependencies:
- dependency-name: openvino
  dependency-version: 2026.4.1
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

docker/main/requirements-ov.txt

@@ -1,2 +1,2 @@
 numpy
-openvino >= 2026.2.0
+openvino >= 2026.4.1

docker/main/requirements-wheels.txt

@@ -42,7 +42,7 @@ opencv-python-headless == 4.11.0.*
 opencv-contrib-python == 4.11.0.*
 scipy == 1.17.*
 # OpenVino & ONNX
-openvino == 2025.4.*
+openvino == 2026.4.*
 onnxruntime == 1.30.*
 # Embeddings
 transformers == 5.19.*