fix(mcp): start OAuth when initialize succeeds without tokens

[Epochex]

What

Fix MCP OAuth authorization flow for servers that return 200 OK on initialize even when no tokens are present.

Today ToolMCPAuthApi marks the provider as authed=true as soon as it can connect, which breaks OAuth-protected servers like Google Drive MCP: initialize succeeds, but later tool calls fail because no access token was ever obtained.

How

After a successful connect, if the provider has client_information configured but still has no tokens, start the OAuth flow via core.mcp.auth.auth_flow.auth() and return the authorization_url response instead of saving authed=true.

Tests

• uv run --project api pytest -q api/tests/unit_tests/controllers/console/workspace/test_tool_providers.py -k mcp_auth
• uv run --project api ruff check api/controllers/console/workspace/tool_providers.py api/tests/unit_tests/controllers/console/workspace/test_tool_providers.py

Fixes #36230

[Epochex]

Actions checks haven’t started for this fork PR yet (workflow runs show “Action required”).

I ran the focused checks locally and they pass:

• uv run --project api pytest -q api/tests/unit_tests/controllers/console/workspace/test_tool_providers.py -k mcp_auth
• uv run --project api ruff check api/controllers/console/workspace/tool_providers.py api/tests/unit_tests/controllers/console/workspace/test_tool_providers.py

Could a maintainer please approve/run the workflows so CI can execute?