Need to remove style attribute, if value of style attribute is nil | false

[sundaramss]

defstyles function is not eliminate/remove the style attribute, if value of attribute is nil/false.
ex:

(defstyles cell [& {borderColor :border-color :or {borderColor nil}}]
 {
  :width "100%"
  :height "36px"
  :border (when borderColor
                 (str "1px solid " borderColor))})

• [:div {:class (cell)}]
  output of style is

			
.vars--591108371 {
    --var-sample-app_appcss__cell-0: ;
}

.sample-app_appcss__cell {
    width: 100%;
    height: 36px;
    border: var(--var-sample-app_appcss__cell-0);
}