fix(ui): use local activeResponse in finally block to prevent TypeError

[kaigritun]

Summary

This PR fixes a bug where this.activeResponse could be undefined in the finally block of makeRequest, causing a TypeError when calling onFinish.

Problem

The issue occurred when:

1. An error was thrown before this.activeResponse was assigned
2. A concurrent makeRequest call overwrote this.activeResponse

This caused:

TypeError: Cannot read properties of undefined (reading 'state')

Solution

The fix uses a local variable to capture activeResponse at the start of the try block:

1. Declare let activeResponse before the try block
2. Assign to the local var in the try block
3. Use the local var with null check in the finally block

This ensures the reference is stable and available even if this.activeResponse is modified by concurrent operations.

Credit

Thanks to @codybrouwers for identifying the root cause and providing the patch in the issue comments.

Fixes #8477