chore(deps): update homeassistant requirement

Updates the requirements on [homeassistant](https://github.com/home-assistant/core) to permit the latest version.
- [Release notes](https://github.com/home-assistant/core/releases)
- [Commits](home-assistant/core@2024.11.0...2026.9.1)

---
updated-dependencies:
- dependency-name: homeassistant
  dependency-version: 2026.9.1
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

requirements-test.txt

@@ -1,7 +1,7 @@
 # Test Requirements
 # aiohttp is intentionally not listed: homeassistant pins an exact aiohttp
 # version, and any additional constraint here makes pip's resolver fail.
-homeassistant>=2024.11.0
+homeassistant>=2026.9.1
 pytest>=9.1.1
 pytest-asyncio>=0.21.0
 pytest-cov>=7.1.0