Copilot: Updating Fable ability following Anthropic's announcement (#61724)

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

Author: crwaters16

content/copilot/reference/copilot-billing/models-and-pricing.md

@@ -43,6 +43,8 @@ All prices are **per 1 million tokens**.
 
 Anthropic models include a cache write cost in addition to cached input.
 
+{% data reusables.copilot.model-fable-disabled %}
+
 | Model | Release status | Category | Input | Cached input | Cache write | Output |
 | --- | --- | --- | ---: | ---: | ---: | ---: |
 | {% for entry in tables.copilot.models-and-pricing %}{% if entry.provider == "anthropic" %} |

data/reusables/copilot/model-fable-disabled.md

@@ -0,0 +1 @@
+> [!NOTE] Claude Fable 5 is currently unavailable. For more information, see [Anthropic's announcement](https://www.anthropic.com/news/fable-mythos-access).