The SEO fields in Page Properties > Advanced Properties collect meta description and meta keywords. A simple regex string replace here to remove leading & trailing white space.
#set($RegexPatternLeadingWhiteSpaceTrailingLineBreaks = "(^\s*|[\n\t\r])") #if ($UtilMethods.isSet($HTMLPAGE_KEYWORDS)) <META name="keywords" lang="en-us" content="$HTMLPAGE_KEYWORDS.replaceAll($RegexPatternLeadingWhiteSpaceTrailingLineBreaks, "")"> #end #if ($UtilMethods.isSet($HTMLPAGE_DESCRIPTION)) <META name="description" lang="en-us" content="$HTMLPAGE_DESCRIPTION.replaceAll($RegexPatternLeadingWhiteSpaceTrailingLineBreaks, "")"> #end