Update issue reporting guidelines in README (#4502)

* Update issue reporting guidelines in README

Added guidelines for reporting issues with reproduction code.

* Update README.md

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

* Update issue reporting instructions in README

Clarified the issue reporting policy regarding code submissions.

---------

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

Author: vnbaaij

README.md

@@ -10,6 +10,17 @@
 [![Validate Security](https://github.com/microsoft/fluentui-blazor/actions/workflows/codeql-analysis.yml/badge.svg)](https://github.com/microsoft/fluentui-blazor/actions/workflows/codeql-analysis.yml)
 -->
 
+> ## Reporting an issue?
+> Please supply us with **ready-to-run** reproduction code in the form of something we can copy/paste, a (zipped) project structure or a GitHub repository.
+>
+> We do not have capacity to craft or compose a reproduction for every issue that gets raised.
+>
+> If no code or repository is provided, the issues will be closed after 3 days.
+>
+> Help us to help you. Thanks.
+>
+> With 💖, the Fluent UI crew.
+
 ## Demo
 Explore the Demo: visit https://www.fluentui-blazor.net to kickstart your first project, browse the documentation, and test all components live.  
 If you encounter any problems, you can use the [backup site](https://fluentui-blazor.azurewebsites.net).