ci: Pinning the server build runs to Ubuntu 22.04 because of Flapdoodle errors (#38723)

## Description
Flapdoodle, our Mongo embedded testing library throws errors when
running Junit tests on Ubuntu 24.04. This is because of a mismatch of
openssl version from Ubuntu 22.04 to Ubuntu 24.04. Hence pinning our CI
for server builds to Ubuntu 22.04 for now. Will issue a holistic fix
with Flapdoodle upgrade later.

## Automation

/ok-to-test tags=""

### 🔍 Cypress test results
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> [!CAUTION]  
> If you modify the content in this section, you are likely to disrupt
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## Communication
Should the DevRel and Marketing teams inform users about this change?
- [ ] Yes
- [ ] No


<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->

## Summary by CodeRabbit

- **Chores**
- Updated GitHub Actions workflow configurations for server build and
integration tests
- Migrated workflow environments from `ubuntu-latest-8-cores` to
`ubuntu-22.04-8core`
	- Refined workflow logic for test execution and artifact management

<!-- end of auto-generated comment: release notes by coderabbit.ai -->

.github/workflows/server-build.yml

@@ -51,7 +51,7 @@ defaults:
 
 jobs:
   server-unit-tests:
-    runs-on: ubuntu-latest-8-cores
+    runs-on: ubuntu-22.04-8core
 
     # Service containers to run with this job. Required for running tests
     services:
@@ -302,7 +302,6 @@ jobs:
               exit 1
           fi
 
-
       # Set status = failedtest
       - name: Set fail if there are test failures
         if: failure()

.github/workflows/server-integration-tests.yml

@@ -17,7 +17,7 @@ on:
 
 jobs:
   run-tests:
-    runs-on: ubuntu-latest-8-cores
+    runs-on: ubuntu-22.04-8core
     if: |
       github.event.pull_request.head.repo.full_name == github.repository ||
       github.event_name == 'workflow_dispatch'
@@ -104,5 +104,3 @@ jobs:
           # Run tests and capture logs
           cd app/server
           mvn verify -DskipUTs=true "${args[@]}" | tee mvn_integration_test.log
-
-