import: add a debugging log of importing blob

This should be helpful for debugging issue #38524.

src/import/import-compress.c

@@ -4,6 +4,7 @@
 #include <string.h>
 
 #include "import-compress.h"
+#include "log.h"
 #include "string-table.h"
 
 void import_compress_free(ImportCompress *c) {
@@ -104,6 +105,7 @@ int import_uncompress_detect(ImportCompress *c, const void *data, size_t size) {
 
         c->encoding = false;
 
+        log_debug("Detected compression type: %s", import_compress_type_to_string(c->type));
         return 1;
 }