Fix render_in to return html_safe empty string when render? is false

Co-authored-by: joelhawksley <1940294+joelhawksley@users.noreply.github.com>
Agent-Logs-Url: https://github.com/ViewComponent/view_component/sessions/bfc044d6-6ca7-4999-a544-ff12b3f1b00d

Author: Copilot

lib/view_component/base.rb

@@ -160,7 +160,7 @@ def render_in(view_context, &block)
 
         value
       else
-        ""
+        "".html_safe
       end
     ensure
       view_context.instance_variable_set(:@virtual_path, @old_virtual_path)

test/sandbox/test/rendering_test.rb

@@ -877,6 +877,12 @@ def test_does_not_render_passed_in_content_if_render_is_false
     assert total < 1
   end
 
+  def test_render_in_returns_html_safe_string_when_render_is_false
+    render_inline(ConditionalRenderComponent.new(should_render: false))
+
+    assert_predicate @rendered_content, :html_safe?
+  end
+
   def test_collection_parameter_does_not_require_compile
     dynamic_component =
       Class.new(ViewComponent::Base) do