Use protobuf provided by ports

Index: Ghidra/Test/DebuggerIntegrationTest/src/test.slow/java/agent/gdb/rmi/GdbConnectorsTest.java
--- Ghidra/Test/DebuggerIntegrationTest/src/test.slow/java/agent/gdb/rmi/GdbConnectorsTest.java.orig
+++ Ghidra/Test/DebuggerIntegrationTest/src/test.slow/java/agent/gdb/rmi/GdbConnectorsTest.java
@@ -53,7 +53,7 @@ public class GdbConnectorsTest extends AbstractRmiConn
 		// Make sure system doesn't cause path failures to pass
 		unpip("ghidragdb", "ghidratrace");
 		// Ensure a compatible version of protobuf
-		pip("protobuf==6.31.0");
+		pip("protobuf==${PROTOBUF_VER}");
 	}
 
 	@Test
