refactor(charts): wrap AvailablePresets ReadDir error

The companion fn to PresetFiles still returned a raw fs.PathError
behind a nolint:wrapcheck directive while PresetFiles wraps with
errors.Wrap. Match the pattern: errors.Wrap with the operation
description so an embedded-FS failure surfaces with context, not
just a bare path error.

Signed-off-by: Aleksei Sviridkin <f@lex.la>

Author: lexfrei

charts/charts.go

@@ -76,7 +76,7 @@ func AvailablePresets() ([]string, error) {
 
 	entries, err := embeddedCharts.ReadDir(".")
 	if err != nil {
-		return nil, err //nolint:wrapcheck // wrapper around embedded FS ReadDir.
+		return nil, errors.Wrap(err, "reading embedded charts root")
 	}
 
 	for _, entry := range entries {