Revert "RNA: error on register when classes use invalid identifiers"

This reverts commit b24a255ca6.

The warning wasn't being printed, so many add-ons weren't yet updated.

Re-enable now warnings are printed to allow addon developers to update.

source/blender/makesrna/intern/rna_access.c

@@ -1017,8 +1017,14 @@ bool RNA_struct_bl_idname_ok_or_report(ReportList *reports, const char *identifi
 	const int len_sep = strlen(sep);
 	const int len_id = strlen(identifier);
 	const char *p = strstr(identifier, sep);
+	/* TODO: make error, for now warning until add-ons update. */
+#if 1
+	const int report_level = RPT_WARNING;
+	const bool failure = true;
+#else
 	const int report_level = RPT_ERROR;
 	const bool failure = false;
+#endif
 	if (p == NULL || p == identifier || p + len_sep >= identifier + len_id) {
 		BKE_reportf(reports, report_level, "'%s' doesn't contain '%s' with prefix & suffix", identifier, sep);
 		return failure;