Improve KFS request validation

[atobiszei]

JIRA:CVS-192922

[Copilot]

Pull request overview

This PR improves KServe (KFS) request validation by centralizing and extending coherency checks for raw_input_contents, and adds regression tests to ensure invalid requests are rejected consistently across both predict and MediaPipe paths.

Changes:

• Added a coherency validation that rejects requests where raw_input_contents.size() != inputs_size().
• Removed a duplicated raw_input_contents vs inputs count check from the MediaPipe graph execution path in favor of the centralized validator.
• Added unit tests covering the raw input contents count mismatch for both predict validation and MediaPipe inference.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 2 comments.

File	Description
src/test/predict_validation_test.cpp	Adds a test case asserting invalid status when raw input buffer count doesn’t match input tensor count.
src/test/mediapipe_validation_test.cpp	Adds a test case asserting MediaPipe infer rejects raw buffer count mismatches.
src/kfs_frontend/kfs_utils.cpp	Adds centralized raw_input_contents vs inputs_size() coherency validation and updates includes.
src/kfs_frontend/kfs_graph_executor_impl.cpp	Removes the local raw buffer count check now covered by centralized validation.

---

💡 Add a code-review agent skill or configure MCP servers for context-aware, tailored reviews. Learn more in the docs.