🐛✅ SSE event could start with id

[evaline-ju]

Summary

For a tool on the everything MCP server registered through MCP gateway, instead of getting an expected tool response block, the tool response was let through with error logs in the adapter

DEBUG:ext-proc-PM:Response body text: ['id:
f1833ebe-5ad3-4c9f-8acf-4117f8c76d4e_1775582473900_fvcrthoy', 'data: ', '', 'event: message', 'id:
f1833ebe-5ad3-4c9f-8acf-4117f8c76d4e_1775582473900_esl5mn10', 'data:
{"result":{"content":[{"type":"text","text":"Echo: my password is secret"}]},"jsonrpc":"2.0","id":10}', '', '']
ERROR:ext-proc-PM:Failed to parse JSON: Expecting value: line 1 column 1 (char 0).

This PR fixes this and adds a unit test for the case where the event starts with id

Related issue(s)

Fixes #92

[julianstephen]

Looks gd.