chore(apigw): add abort_with_json as an util, allow config httpx client limits

[gi0baro]

SSIA

[cursor]

Cursor Bugbot has reviewed your changes and found 1 potential issue.

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[sentry]

Bug: The abort_with_json function may not set the Content-Type header correctly on error responses because response.content_type might not update response.headers immediately.
_{Severity: MEDIUM}

Suggested Fix

Instead of assigning to response.content_type, directly set the header in the response.headers dictionary before raising the exception, for example: response.headers["Content-Type"] = "application/json".

Prompt for AI Agent

Review the code at the location below. A potential bug has been identified by an AI
agent. Verify if this is a real issue. If it is, propose a fix; if not, explain why it's
not valid.

Location: src/apigw/utils.py#L10-L13

Potential issue: In the `abort_with_json` function, setting `response.content_type =
"application/json"` may not synchronously update the `response.headers` dictionary. The
function then immediately raises an `HTTPBytesResponse` using the potentially outdated
`response.headers`. This can result in an error response being sent with a JSON body but
without the corresponding `Content-Type: application/json` header, which could cause
clients to fail to parse the error message correctly.

_{Did we get this right? 👍 / 👎 to inform future reviews.}

[mwarkentin]

LGTM