Using both Bun and Express leads to "express is not instrumented" warning (Bun not publishing to http Diagnostic Channel)

### Is there an existing issue for this?

- [x] I have checked for existing issues https://github.com/getsentry/sentry-javascript/issues
- [x] I have reviewed the documentation https://docs.sentry.io/
- [x] I am using the latest SDK release https://github.com/getsentry/sentry-javascript/releases

### How do you use Sentry?

Sentry Saas (sentry.io)

### Which SDK are you using?

@sentry/bun

### SDK Version

10.15.0

### Framework Version

Express 5.1.0

### Link to Sentry event

_No response_

### Reproduction Example/SDK Setup

https://github.com/RudolfSchreier/sentry-express-bun-demo

### Steps to Reproduce

1. Get a working SENTRY_DSN for some project
2. start the demo using `env SENTRY_DSN=... bun run dev`

### Expected Result

The express server starts up with working Sentry integration and no warnings.

### Actual Result

The express server starts up, but with a Sentry warning about missing instrumentation:
> [Sentry] express is not instrumented. Please make sure to initialize Sentry in a separate file that you `--import` when running node, see: https://docs.sentry.io/platforms/javascript/guides/express/install/esm/.

### Additional Context

When using both Bun and Express, it is unclear which SDK to preferably use (@sentry/node or @sentry/bun), but both appear to show this issue.

It is unclear if the warning is correct or erroneous (and Express integration is actually working).

It is unclear to me from the description of https://github.com/getsentry/sentry-javascript/issues/13674 if this the expected result for Express v5.

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