fix(spoof): skip empty PIF source files

resolvePifPatch selected the last existing file regardless of
size. A 0-byte file picked up by lastOrNull caused JSONObject("")
to throw, the catch silently fell back to SystemProperties, and a
preceding non-empty PIF was ignored. Filter out zero-length files
so the lookup walks past them to the next valid candidate.

app/src/main/java/org/matrix/TEESimulator/config/PatchLevelManager.kt

@@ -93,7 +93,9 @@ object PatchLevelManager {
     }
 
     private fun resolvePifPatch(): String? {
-        val source = PIF_SOURCES.map(::File).lastOrNull { it.exists() } ?: return null
+        val source =
+            PIF_SOURCES.map(::File).lastOrNull { it.exists() && it.length() > 0 }
+                ?: return null
         return try {
             val text = source.readText()
             val parsed =