public String getMetadataKey() {
			return metadataKey;
		}
Notify the index instance management that a Project has been closed.  Users of this service
need to do this because notification of Project closure is only available to GUI Plugin
classes.

@param project {@link Project} that was closed
Ghidra/Features/Base/src/main/java/ghidra/plugin/importer/ProjectIndexService.java