Prepend internal/ to schedule branch filter in sqlclient-kerberos pipeline (#4284)

* Prepend internal/ to schedule branch filter in sqlclient-kerberos pipeline

Agent-Logs-Url: https://github.com/dotnet/SqlClient/sessions/32560c75-1937-4a17-b776-4ab714e2bac8

Co-authored-by: paulmedynski <31868385+paulmedynski@users.noreply.github.com>

* Update comment to reflect internal/ branch prefix

Agent-Logs-Url: https://github.com/dotnet/SqlClient/sessions/32560c75-1937-4a17-b776-4ab714e2bac8

Co-authored-by: paulmedynski <31868385+paulmedynski@users.noreply.github.com>

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: paulmedynski <31868385+paulmedynski@users.noreply.github.com>

Author: Copilot

eng/pipelines/kerberos/sqlclient-kerberos.yml

@@ -10,7 +10,7 @@
 # Daily Kerberos authentication test pipeline for Microsoft.Data.SqlClient.
 # Replaces the Classic "Test-SqlClient-Kerberos-Azure" pipeline.
 #
-# Schedule: daily at 08:00 UTC on release/6.1.
+# Schedule: daily at 08:00 UTC on internal/release/6.1.
 #
 # Job breakdown (8 total):
 #   Stage: windows           → 4 jobs  (net8/9 × NativeSNI/ManagedSNI)
@@ -43,7 +43,7 @@ schedules:
     displayName: Daily run (08:00 UTC)
     branches:
       include:
-        - release/6.1
+        - internal/release/6.1
     always: true
 
 name: $(date:yyyyMMdd)$(rev:.r)