Minor fix to reflect the Qiskit transpiler service is on beta status (Q…

…iskit#1458)

In Qiskit#1435 I did not update the status of the Qiskit transpiler service
from "alpha" to "beta".


This PR fixes it

---------

Co-authored-by: abbycross <across@us.ibm.com>

docs/transpile/ai-transpiler-passes.mdx

@@ -10,7 +10,7 @@ The AI-powered transpiler passes are experimental passes that work as a drop-in
 
 <Admonition type="note">
     This is an experimental feature available only to the IBM Quantum Premium Plan.
-    The AI-powered transpiler passes are in alpha release status, subject to change.
+    The AI-powered transpiler passes are in beta release status, subject to change.
     If you have feedback or want to contact the developer team, please use this [Qiskit Slack Workspace channel](https://qiskit.slack.com/archives/C06KF8YHUAU).
 </Admonition>
 

docs/transpile/qiskit-transpiler-service.mdx

@@ -11,7 +11,7 @@ The Qiskit transpiler service offers a Python library to seamlessly integrate th
 
 <Admonition type="note">
     This experimental service is only available for IBM Quantum Premium Plan users.
-    The service is an alpha release, subject to change.
+    The service is a beta release, subject to change.
     If you have feedback or want to contact the developer team, please use this [Qiskit Slack Workspace channel](https://qiskit.slack.com/archives/C06KF8YHUAU).
 </Admonition>