feat: Fixes #1940 WCAG support for website widget (#2071)

Co-authored-by: Kaj Oudshoorn <kaj@milvum.com>
Co-authored-by: Pranav Raj S <pranav@chatwoot.com>
Co-authored-by: Nithin David Thomas <1277421+nithindavid@users.noreply.github.com>

app/javascript/widget/components/ChatAttachment.vue

@@ -68,13 +68,19 @@ export default {
 </script>
 <style scoped lang="scss">
 @import '~widget/assets/scss/variables.scss';
+@import '~widget/assets/scss/mixins.scss';
 
 .attachment-button {
+  @include button-size;
+
   background: transparent;
   border: 0;
   cursor: pointer;
   position: relative;
   width: 20px;
+  display: flex;
+  align-items: center;
+  justify-content: center;
 
   i {
     font-size: $font-size-large;