Checkbox: Restore checkmark icon in context bundles

The legacy .tf-checkbox checked rule uses the background shorthand, which
resets background-image and wiped the TUI checkbox's SVG checkmark inside
context bundles (WP context showed no icon at all, since the WP theme also
hides the core ::before dashicon). Scope the legacy rule away from TUI
inputs with :not(.tui-inline-choice__control), same pattern as Notice.

Includes rebuilt assets.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

Author: juliacanzani

assets/build/beaver-builder/index.min.css

@@ -6,7 +6,9 @@
 		margin-bottom: revert;
 	}
 
-	input[type="checkbox"] {
+	/* Legacy checkbox only — the background shorthand below would wipe the
+	   TUI checkbox's background-image checkmark */
+	input[type="checkbox"]:not(.tui-inline-choice__control) {
 	  box-shadow: 0 0 0 transparent;
 		border: $field-border-width $field-border-style $field-font-color;
 		margin-right: $label-spacer;