fix libtags m4a issue

lib/libtags/tags.c

@@ -46,7 +46,8 @@ tagscallcb(Tagctx *ctx, int type, const char *k, char *s, int offset, int size,
 		e = s + strlen(s);
 		while(e != s && (uchar)e[-1] <= ' ')
 			e--;
-		*e = 0;
+		if (*e != 0)
+			*e = 0;
 	}
 	if(*s){
 		ctx->tag(ctx, type, k, s, offset, size, f);

src/database/tag_parser.cpp

@@ -113,12 +113,6 @@ auto TagParserImpl::ReadAndParseTags(const std::string& path, TrackTags* out)
     }
   }
 
-  if (path.ends_with(".m4a")) {
-    // TODO(jacqueline): Re-enabled once libtags is fixed.
-    ESP_LOGW(kTag, "skipping m4a %s", path.c_str());
-    return false;
-  }
-
   libtags::Aux aux;
   aux.tags = out;
   if (f_stat(path.c_str(), &aux.info) != FR_OK ||