refactor(sound): streamline OpenAL device handling and enhance test stubs

- Removed conditional compilation for OpenAL device and context in snd_openal.c, simplifying the code structure.
- Updated MSG_Init function in test_net_protocol_validation.c to provide a more complete stub implementation for testing purposes.
- Improved clarity and maintainability of sound-related code by eliminating unnecessary preprocessor directives.

Author: timfox

src/client/snd_openal.c

@@ -7,13 +7,8 @@
 
 // Global variables for OpenAL state (available even when OpenAL is not compiled)
 int numOpenALSounds = 0;
-#ifdef USE_OPENAL
-ALCdevice *openalDevice = NULL;
-ALCcontext *openalContext = NULL;
-#else
 void *openalDevice = NULL;
 void *openalContext = NULL;
-#endif
 qboolean openalEfxAvailable = qfalse;
 
 #ifdef USE_OPENAL

src/tests/test_net_protocol_validation.c

@@ -13,7 +13,16 @@ Tests network protocol validation and bounds checking functionality
 #include <string.h>
 
 // Stub for MSG_Init (not available in test environment)
-void MSG_Init(void) {}
+void MSG_Init(msg_t *buf, byte *data, int length) {
+    // Stub implementation for testing
+    if (buf) {
+        buf->data = data;
+        buf->maxsize = length;
+        buf->cursize = 0;
+        buf->readcount = 0;
+        buf->bit = 0;
+    }
+}
 
 // Test data
 static const byte valid_packet_data[] = {