[MSTeams] Messages after tool execution not delivered

Description

When using OpenClaw with Microsoft Teams, messages sent after tool execution are not being delivered to the user.

Steps to Reproduce

1. User asks agent to perform a task (e.g., security check)
2. Agent responds with 'I will check now'
3. Agent executes tool (e.g., openclaw security audit)
4. Agent sends result message

Expected Behavior

Both messages (before and after tool execution) should be delivered to the user.

Actual Behavior

Only the first message ('I will check now') is delivered. The result message after tool execution is not shown in Teams.

Notes

• This issue does NOT occur with Slack - both messages are delivered correctly
• Occurs with both short and long messages after tool execution
• User has to ask 'What happened?' to get the result re-sent

Environment

• OpenClaw channel: stable
• Platform: macOS 26.2 (arm64)
• Node: 25.5.0