Fix report dialog being illegible using mastodon-light theme (#17734)

Fixes #17726

app/javascript/styles/mastodon-light/diff.scss

@@ -143,10 +143,15 @@ html {
 .box-widget input[type="password"],
 .box-widget textarea,
 .statuses-grid .detailed-status,
+.report-dialog-modal__textarea,
 .audio-player {
   border: 1px solid lighten($ui-base-color, 8%);
 }
 
+.report-dialog-modal .dialog-option .poll__input {
+  color: $white;
+}
+
 .search__input {
   @media screen and (max-width: $no-gap-breakpoint) {
     border-top: 0;
@@ -342,6 +347,7 @@ html {
 .mute-modal,
 .block-modal,
 .report-modal,
+.report-dialog-modal,
 .embed-modal,
 .error-modal,
 .onboarding-modal,