myloader report "Global metadata file processing was not possible" when import the sql files exported by dumpling

## Enhancement
myloader version : 0.14.5-2

An error is reported when using myloader to import the sql files exported by dumpling . The current workaround is to comment out all the content in the metadata file.
It seems that the metadata file exported by dumpling needs to be compatible.

[root@172-16-120-238 dumptest]# myloader -h xxxxxxx -P xxxx -d xxxx

** (myloader:187498): WARNING **: 15:21:05.098: Failed to load config file //home/tidb/hwtest/dumptest/metadata: Key file contains line “Started dump at: 2023-06-25 14:33:58” which is not a key-value pair, group, or comment

** (myloader:187498): ERROR **: 15:21:05.098: Global metadata file processing was not possible
Trace/breakpoint trap