Consider limiting processes where Segment Heap is enabled

## Description
After enabling Segment Heap on Windows (#1539) (#1541), we have seen few user reports claiming enabling Segment Heap might have triggered compatibility issues with other 3rd party software, notably 3rd party security software.

* https://support.google.com/gboard/thread/457605380/

While such compatibility issues are expected to disappear sooner or later as Visual Studio 2026 finally started promoting this opt-in setting [by default](https://devblogs.microsoft.com/cppblog/segment-heap-support-for-c-projects-in-visual-studio/), it would be safer to enable Segment Heap only in selected processes for now.

As above compatibility reports are limited to GUI processes such as `mozc_tool.exe` and `mozc_renderer.exe`, one of safer choice would be enabling Segment Heap only in `mozc_server.exe`, where we can expect the biggest performance gain.

## Version or commit-id
3f235b4eb6fcff7d14ef5f0fb8ee56de7ee4c732

## Environment
- OS: Reportedly Windows 11 26200.9168
- "Deep Instinct" is installed and running

## Additional context
Reportedly the following 3rd party DLLs were loaded into the GUI tool process.
* C:\Program Files\DeepInstinct\x64\DI_ws2_32.dll
* C:\Program Files\DeepInstinct\x64\DI_ntdll.dll
* C:\Program Files\DeepInstinct\x64\DI_kernel32.dll
* C:\Program Files\DeepInstinct\x64\DeepCI.dll