.github/workflows: Migrate workflows to Blacksmith runners (#9504)

To whomever may be reviewing this PR,

**[Blacksmith](https://www.blacksmith.sh/) is the fastest way to run
your GitHub Actions.**

## What does this PR change?

This PR has been automatically generated by a team member in your GitHub
organization using Blacksmith's [Migration
Wizard](https://docs.blacksmith.sh/introduction/quickstart), or MigWiz
for short. This PR changes the following:

1. Your selected workflows will now run on Blacksmith's 2x faster
hardware (e.g., `runs-on: blacksmith-4vcpu-ubuntu-2204`). Learn more
about the [different instances available to choose
from](https://docs.blacksmith.sh/blacksmith-runners/config).
2. Your jobs running on Blacksmith will now have all official GitHub and
popular third-party cache actions automatically interact with our 4x
faster, colocated cache. Learn more about [Blacksmith's actions
cache](https://docs.blacksmith.sh/blacksmith-caching/dependencies-actions).
3. Your GitHub Actions will now actually be observable. Learn more about
Blacksmith's
[logging](https://docs.blacksmith.sh/blacksmith-observability/logs) and
other
[observability](https://docs.blacksmith.sh/blacksmith-observability/dashboard)
features.
4. Your Docker builds will now automatically share their Docker layer
cache, resulting in up to 40x faster builds. Learn more about
[Blacksmith's Docker layer
caching](https://docs.blacksmith.sh/blacksmith-caching/docker-builds).

## FAQ

- Is this free? The first 3,000 minutes per month are free.
- Who uses Blacksmith? Clerk, Ashby, VEED, and 600+ others.
- What's the catch? There is none. Merge this thing already.

Co-authored-by: blacksmith-sh[bot] <157653362+blacksmith-sh[bot]@users.noreply.github.com>

Author: blacksmith-sh[bot]

.github/workflows/cd-dgraph.yml

@@ -121,7 +121,7 @@ jobs:
           path: dgraph-standalone-amd64.tar
 
   dgraph-build-arm64:
-    runs-on: ubuntu-latest-arm
+    runs-on: blacksmith-4vcpu-ubuntu-2404-arm
     timeout-minutes: 15
     steps:
       - uses: actions/checkout@v5

.github/workflows/ci-dgraph-tests-arm64.yml

@@ -23,7 +23,7 @@ permissions:
 jobs:
   dgraph-tests:
     if: github.event.pull_request.draft == false
-    runs-on: ubuntu-latest-arm
+    runs-on: blacksmith-4vcpu-ubuntu-2404-arm
     timeout-minutes: 60
     steps:
       - uses: actions/checkout@v5