Fix pip invocation and error handling for ninja install in whisper_jump_times.py (#27685)
### Description
- Changed ninja pip install command from `["pip", "install", "ninja"]`
to `[sys.executable, "-m", "pip", "install", "ninja"]` to ensure
installation targets the active Python environment (venv/conda) rather
than an arbitrary `pip` on PATH.
- Wrapped `subprocess.run` in a `try/except
subprocess.CalledProcessError` block that logs a clear error via
`logger.error` before re-raising, replacing a silent unhandled
exception.
- Added `import sys`.
**Before:**
```python
install_cmd = ["pip", "install", "ninja"]
logger.warning(f"Could not import `ninja`. Attempting to install `ninja` via `{' '.join(install_cmd)}`.")
subprocess.run(install_cmd, check=True)
```
**After:**
```python
install_cmd = [sys.executable, "-m", "pip", "install", "ninja"]
logger.warning(f"Could not import `ninja`. Attempting to install `ninja` via `{' '.join(install_cmd)}`.")
try:
subprocess.run(install_cmd, check=True)
except subprocess.CalledProcessError as install_err:
logger.error(f"Failed to install `ninja`: {install_err}", exc_info=True)
raise
```
### Motivation and Context
Using bare `pip` can silently install into the wrong environment and
fails if `pip` is not on PATH. The unhandled `CalledProcessError` on
install failure produced no actionable log output. Addresses feedback
from [#27684](https://github.com/microsoft/onnxruntime/pull/27684).
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Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: apsonawane <111780983+apsonawane@users.noreply.github.com>