fix(logger): Fix default subst

Default variable substitution in plain-text function was incorrect.

logger.sh

@@ -72,7 +72,7 @@ writePlainTextLog() {
 
   printf "%s %s %s[%s]: [%s] [%s] %s (%s:%s)\n" \
     "$(getTimeStamp)" "$(getHostname)" "$LOG_PROGRAM_NAME" "$$" \
-    "$2" "$(standardizeLogLevels "$3")" "$1" "${4:UNSPECIFIED}" "${5:999}"
+    "$(standardizeLogLevels "$2")" "$(uppercase "$3")" "$1" "${4:-UNSPECIFIED}" "${5:-999}"
 }
 
 # $1: message, $2: level, $3: status, [$4: operation], [$5: code]