gitlab-ci: Switch to using Bookworm (LTS) for doing code coverage

The initial step from gcov/lcov gives a few parsing errors like
'mismatched end line' or 'mismatched exception tag for'.

Been trying with llvm-cov, downgrading to gcc-13 and using different
gcov versions including one from oldoldstable -- I'm repeatably getting
these errors.

I turned instead of the idea to use our previous stable version, now the
oldstable/LTS as that was capable of doing code coverage.  So possibly
either gcc-13 is the first version that causes these issues but we're
having gcc-14 in Trixie so it doesn't really matter. For now use this
work-around until we have something better.

Signed-off-by: Marius Vlad <marius.vlad@collabora.com>

.gitlab-ci.yml

@@ -455,11 +455,6 @@ aarch64-debian-container_prep:
 x86_64-debian-lts-full-build:
   extends:
     - .test-env-debian-lts-x86_64
-    - .build-options-full-v2
-
-x86_64-debian-full-build:
-  extends:
-    - .test-env-debian-x86_64
     - .build-options-full
   artifacts:
     reports:
@@ -467,6 +462,11 @@ x86_64-debian-full-build:
         coverage_format: cobertura
         path: $BUILDDIR/meson-logs/coverage.xml
 
+x86_64-debian-full-build:
+  extends:
+    - .test-env-debian-x86_64
+    - .build-options-full-v2
+
 aarch64-debian-lts-full-build:
   extends:
     - .test-env-debian-lts-aarch64
@@ -612,18 +612,18 @@ x86_64-debian-no-vulkan-build:
 docs-and-coverage:
   extends:
     - .default-rules
-    - .debian-x86_64
+    - .debian-lts-x86_64
     - .fdo.suffixed-image@debian
   stage: pages
   needs:
     - job: docs-build
       artifacts: true
-    - job: x86_64-debian-full-build
+    - job: x86_64-debian-lts-full-build
       artifacts: true
   timeout: 5m
   script:
   - mv prefix-weston-docs-build/share/doc/weston Documentation
-  - mv build-weston-x86_64-debian-full-build/meson-logs/coveragereport Test_Coverage
+  - mv build-weston-x86_64-debian-lts-full-build/meson-logs/coveragereport Test_Coverage
   - rm Test_Coverage/gcov.css
   - cp doc/style/lcov-style.css Test_Coverage/gcov.css
   - cp doc/style/*.png Test_Coverage/