Do not mention deprecated reuse policy (#4408)

Co-authored-by: Milecia McG <47196133+flippedcoder@users.noreply.github.com>

Author: dandavison

docs/encyclopedia/activities/standalone-activity.mdx

@@ -71,7 +71,7 @@ The pre-release of Standalone Activities is recommended for experimental use onl
 General limitations:
 - Not suitable for production use cases during Pre-release
 - Delete, pause, reset, and update options are not supported yet
-- The `TerminateExisting` conflict policy and `TerminateIfRunning` reuse policy are not supported yet
+- The `TerminateExisting` conflict policy is not supported yet
 
 Temporal Cloud limitations:
 - Standalone Activities are free for evaluation purposes during Pre-release, so we reserve the right to limit usage if it exceeds a reasonable amount