ci: runners usage optimisation (#2500)

## What ❔
Change runer type for some jobs

## Why ❔
Runner usage optimisation

## Checklist

<!-- Check your PR fulfills the following items. -->
<!-- For draft PRs check the boxes as you complete them. -->

- [x] PR title corresponds to the body of PR (we generate changelog
entries from PRs).
- [x] Tests for the changes have been added / updated.
- [x] Documentation comments have been added / updated.
- [x] Code has been formatted via `zk fmt` and `zk lint`.

.github/workflows/ci.yml

@@ -15,7 +15,7 @@ concurrency:
 
 jobs:
   changed_files:
-    runs-on: [matterlabs-default-infra-runners]
+    runs-on: ubuntu-latest
     name: Get changed files
     outputs:
       core: ${{ steps.changed-files.outputs.core_any_changed }}

.github/workflows/release-please-cargo-lock.yml

@@ -6,7 +6,7 @@ on:
 name: release-please-update-cargo-lock
 jobs:
   update_cargo_lock:
-    runs-on: [matterlabs-ci-runner]
+    runs-on: [matterlabs-default-infra-runners]
 
     steps:
       - uses: actions/checkout@a5ac7e51b41094c92402da3b24376905380afc29 # v4

.github/workflows/release-test-stage.yml

@@ -10,7 +10,7 @@ concurrency:
 
 jobs:
   changed_files:
-    runs-on: [matterlabs-default-infra-runners]
+    runs-on: ubuntu-latest
     name: Test changed-files
     outputs:
       core: ${{ steps.changed-files-yaml.outputs.core_any_changed }}