StandardisePhoneNumber to trim space and check for empty string

string_utils/string_utils.go

@@ -69,6 +69,12 @@ func IsNumericString(s string) bool {
 
 // StandardisePhoneNumber standardises phone numbers with +27 instead of 0 prefix
 func StandardisePhoneNumber(number string) string {
+	number = strings.TrimSpace(number)
+
+	if number == "" {
+		return number
+	}
+
 	// is the first rune/char of the string a 0
 	if []rune(number)[0] == []rune("0")[0] {
 		// Add south african country code (hardcoded for now)