cli formatter: decode the output of the yaml renderer

YAML::XS::Dump returns UTF-8 encoded octets, but the value returned by
a renderer gets encoded when the text output is printed, like any other
value. So for properties using the 'yaml' renderer, for example the
account details shown by 'pvenode acme account info', any non-ASCII
character got encoded twice and ended up mangled.

Decode the output of YAML::XS::Dump in the renderer, so it returns a
character string like all other renderers, and add a test for it.

Fixes: 99d0252 ("properly encode YAML via YAML::XS")
Signed-off-by: Michal Fox <me@dualfroz.com>

src/PVE/CLIFormatter.pm

@@ -27,7 +27,8 @@ PVE::JSONSchema::register_renderer('bytes', \&PVE::Format::render_bytes);
 sub render_yaml {
     my ($value) = @_;
 
-    my $data = YAML::XS::Dump($value);
+    # YAML::XS returns UTF-8 encoded output, but renderers need to return text
+    my $data = decode('UTF-8', YAML::XS::Dump($value));
     $data =~ s/^---[\n\s]//; # remove yaml marker
 
     return $data;