M365 connector regression: Teams chat search tool removed

### What happened?

The Microsoft 365 (Graph) MCP connector no longer exposes chat_message_search, the tool that searched Teams 1:1 and group chat messages. With it gone, there is no way to read Teams direct messages through the connector.

chat_message_search took a query (for example a date like sent:[date], a sender: filter, or a mention pattern) and returned the matching messages across 1:1 and group chats. It did not cover Teams channel conversations. It was present and working as of late June 2026, and is missing by mid-July 2026.

The connector currently exposes only: get_me, outlook_email_search, outlook_calendar_search, outlook_find_available_time, find_meeting_availability, sharepoint_search, sharepoint_folder_search, and read_resource. None of these search Teams chat messages. read_resource can still fetch a single Teams message via a teams:///chats/{chatId}/messages/{messageId} URI, but only if you already have valid IDs, and nothing in the connector produces those IDs anymore.

### What did you expect to happen?

chat_message_search (or an equivalent tool to search Teams 1:1 and group chat messages) should be available, so Teams direct messages can be read through the connector.

### Steps to reproduce

1. Attempt to call the M365 connector's chat_message_search tool.
2. Observe the tool does not exist, and no alternative tool lists or searches Teams chats.

### Area

Tool Discovery / Invocation

### MCP Server (if applicable)

Microsoft 365

### Error messages or logs

```shell

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### Additional context

_No response_