ci(gha): bump timeout for image build (backport of #11533) (#12261)

Automatic cherry-pick of #11533 for branch release-2.7

Generated by
[action](https://github.com/kumahq/kuma/actions/runs/12312318312)

cherry-picked commit 4d7584c
⚠️ ⚠️ ⚠️ Conflicts happened when cherry-picking!
⚠️ ⚠️ ⚠️
```
On branch release-2.7
Your branch is up to date with 'origin/release-2.7'.

You are currently cherry-picking commit 4d7584c.
  (fix conflicts and run "git cherry-pick --continue")
  (use "git cherry-pick --skip" to skip this patch)
  (use "git cherry-pick --abort" to cancel the cherry-pick operation)

Unmerged paths:
  (use "git add <file>..." to mark resolution)
	both modified:   .github/workflows/_build_publish.yaml

no changes added to commit (use "git add" and/or "git commit -a")
```

---------

Signed-off-by: Jakub Dyszkiewicz <jakub.dyszkiewicz@gmail.com>
Signed-off-by: Lukasz Dziedziak <lukidzi@gmail.com>
Co-authored-by: Jakub Dyszkiewicz <jakub.dyszkiewicz@gmail.com>
Co-authored-by: Lukasz Dziedziak <lukidzi@gmail.com>

.github/workflows/_build_publish.yaml

@@ -89,7 +89,7 @@ jobs:
           make publish/pulp
   build-images:
     runs-on: ubuntu-22.04 # pining to this version since we use older base image for kuma-init and we don't want to change it since it can break users environment
-    timeout-minutes: 15
+    timeout-minutes: 30
     strategy:
       fail-fast: false
       matrix: