Remove zero-width whitespace "hack"

app/assets/javascripts/vue_shared/components/markdown/suggestion_diff_row.vue has a comment

      <span v-if="line.text">{{ line.text }}</span>
      <!-- TODO: replace this hack with zero-width whitespace when we have rich_text from BE -->
      <span v-else>&#8203;</span>

#22182 (closed) added display of line.rich_text when available, but we (@thomasrandolph and @kerrizor) didn't have enough context on the hack to know if we could actually remove it. Comment thread