ci: also set TEST_RUNNER environment variable in coverage test

Otherwise, integration-test-wrapper.py will fail.
```
Traceback (most recent call last):
  File "/home/runner/work/systemd/systemd/test/integration-tests/integration-test-wrapper.py", line 693, in <module>
    main()
    ~~~~^^
  File "/home/runner/work/systemd/systemd/test/integration-tests/integration-test-wrapper.py", line 677, in main
    runner = os.environ['TEST_RUNNER']
             ~~~~~~~~~~^^^^^^^^^^^^^^^
  File "<frozen os>", line 717, in __getitem__
KeyError: 'TEST_RUNNER'
```

Follow-up for c0a5801f7b034f3473c10f627d54671e1588963b.

diff --git a/.github/workflows/coverage.yml b/.github/workflows/coverage.yml
index f3ebe4aaafdae84a50748713537a989f92bca13f..7c06507eb1fdf7f60b2a275ad0f76e62f8aaeccb 100644 (file)
--- a/.github/workflows/coverage.yml
+++ b/.github/workflows/coverage.yml
@@ -116,6 +116,8 @@ jobs:
           # used in integration-test-wrapper.py to construct the `gh` command line to download the journals
           # of failed tests.
           sudo --preserve-env mkosi sandbox -- \
+            env \
+            TEST_RUNNER=ubuntu-24.04 \
             meson test \
             -C build \
             --no-rebuild \