Implement Exporter.canExportDomainObject(Class) for Ghidra 12.

Upstream has been dormant since 2021. Ghidra 12 made canExportDomainObject()
take the class rather than an instance, and made it abstract, so this exporter
no longer compiles. Upstream's own prebuilt archives predate the change and do
not implement it either, which means calling it on them raises an
AbstractMethodError.

The exporter handles programs and nothing else, as the export() method below
already asserts.

--- a/src/main/java/orbis/loader/emc/IplExporter.java	2026-09-11 15:12:50.821473500 -0400
+++ b/src/main/java/orbis/loader/emc/IplExporter.java	2026-09-11 15:13:36.712058895 -0400
@@ -34,6 +34,11 @@
     }
 
     @Override
+    public boolean canExportDomainObject(Class<? extends DomainObject> domainObjectClass) {
+        return Program.class.isAssignableFrom(domainObjectClass);
+    }
+
+    @Override
 	public boolean export(File file, DomainObject domainObj, AddressSetView addrSet,
 			TaskMonitor monitor) throws IOException, ExporterException {
         if (!(domainObj instanceof Program)) {