Update dependency eventsource from 2.0.2 to 4.0.0 and remove @types/eventsource

[dskloetc]

Description

The renovate PR to update @types/eventsource to v3 had failures.
While investigating I found that @types/eventsource was removed because the types are included in eventsource starting from version 3.0.0.

Changes

1. Ran yarn remove @types/eventsource.
2. Ran yarn add eventsource.
3. Fixed import statements.
4. Changed EventSource.EventSourceInitDict to EventSourceInit
5. Removed ^ from version after pinned-dependencies.yaml failed.

[github-actions]

NPM Publishing labels 🏷️

🔵 This PR has the none label set and it will not cause a version bump.

[mxiao-cll]

Is this a breaking change? There is one EA using this in the main repo. Can we test it locally to see if that EA is impacted?

If impacted we need to mark this as a major and make changes on EA accordingly

(I am asking because when I tried to do the v3 upgrade it is breaking the main EA)

[dskloetc]

I looked but I couldn't find any EA using this. I searched for SseTransport. The only thing I found was oanda but it creates ModifiedSseTransport which is not related to SseTransport.

Which EA is using this and how did it break for you?

[mxiao-cll]

Yes that oanda EA, I don't quite remember the details but I think it was some types breaking. As long as we can confirm oanda is still good we should be good.

[dskloetc]

I did test Oanda with the framework changes and it appeared unaffected.

[github-actions]

❌ failed to create version bump PR
Failure message: No message provided
Failed job: createVersionBumpPR