refactor(pyghidra_launcher): Improve get_package_version implementation

Refactors the `get_package_version` helper function to use the standard
`importlib.metadata` library instead of a subprocess call to `pip show`.

This change provides several benefits:
- Robustness: Avoids brittle parsing of command-line tool output.
- Performance: Eliminates the overhead of spawning a new process.
- Correctness: The return type hint is corrected to `Optional[str]` to
  accurately reflect that the function can return `None`.
- Simplicity: The unused `python_cmd` parameter has been removed,
  simplifying the function's signature.

Ghidra/Features/PyGhidra/support/pyghidra_launcher.py

@@ -21,7 +21,8 @@ import subprocess
 import sysconfig
 from pathlib import Path
 from itertools import chain
-from typing import List, Dict, Tuple
+from importlib import metadata
+from typing import List, Dict, Tuple, Optional  
 
 def get_application_properties(install_dir: Path) -> Dict[str, str]:
     app_properties_path: Path = install_dir / 'Ghidra' / 'application.properties'
@@ -137,16 +138,14 @@ def version_tuple(v: str) -> Tuple[str, ...]:
         filled.append(point.zfill(8))
     return tuple(filled)
 
-def get_package_version(python_cmd: List[str], package: str) -> str:
-    version = None
-    result = subprocess.run(python_cmd + ['-m', 'pip', 'show', package], capture_output=True, text=True)
-    for line in result.stdout.splitlines():
-        line = line.strip()
-        print(line)
-        key, value = line.split(':', 1)
-        if key == 'Version':
-            version = value.strip()
-    return version
+def get_package_version(package: str) -> Optional[str]:
+    """
+    Checks for an installed package version.
+    """
+    try:
+        return metadata.version(package)
+    except metadata.PackageNotFoundError:
+        return None
 
 def get_saved_python_cmd(install_dir: Path, dev: bool) -> List[str]:
     user_settings_dir: Path = get_user_settings_dir(install_dir, dev)
@@ -269,7 +268,7 @@ def main() -> None:
 
         # If PyGhidra is not installed in the execution environment, offer to install it
         # If it's already installed, offer to upgrade (if applicable)
-        current_pyghidra_version = get_package_version(python_cmd, 'pyghidra')
+        current_pyghidra_version = get_package_version('pyghidra')
         if current_pyghidra_version is None:
             python_cmd = install(install_dir, python_cmd, pip_args, offer_venv)
             if not python_cmd:
@@ -289,6 +288,6 @@ def main() -> None:
     else:
         creation_flags = getattr(subprocess, 'CREATE_NO_WINDOW', 0)
         subprocess.Popen(py_args + remaining, creationflags=creation_flags, stdout=subprocess.DEVNULL, stderr=subprocess.DEVNULL)
- 
+
 if __name__ == "__main__":
     main()