Remove dynamic_layouts from issue template (#149252)

Part of flutter/flutter#148979

The package is being removed from flutter/packages, and so this removes it from the issue template.

Author: Piinks

.github/ISSUE_TEMPLATE/9_first_party_packages.yml

@@ -32,7 +32,6 @@ body:
         - camera
         - cross_file
         - css_colors
-        - dynamic_layouts
         - espresso
         - extension_google_sign_in_as_googleapis_auth
         - file_selector