don't render labels when no label text is provided

[zoul0813]

While working on custom checkbox components that include a label, I've discovered that all fields have a label tag rendered when "fieldTypeHasLabel" returns true. I propose adding an additional check to this function to return false when the field's schema does not have a label property (or altering the v-if statement on the label.

// option 1: add the following to fieldTypeHasLabel(field)
if(isNil(field.label)) 
  return false;

// option 2: alter the label v-if
label(v-if="field.label && fieldTypeHasLabel(field)", :for="getFieldID(field)", :class="field.labelClasses")

This requires the unit tests to be aware of this change as well.

I can submit a PR for this change if approved. Just need to know which option makes more sense.

[icebob]

Good idea. I think option 1 is a good solution.