(fix): Fix Build Image workflow (#158)

This commit fixes build-image workflow. Recent [changes](#148 ) were made to identify Go version using go.mod file. This requires go.mod file to be available before setting up Go.

Workflow failure: https://github.com/llamastack/llama-stack-k8s-operator/actions/runs/17467245024 



Approved-by: nathan-weinberg

Approved-by: rhdedgar

Approved-by: leseb

Author: VaishnaviHire

.github/workflows/build-image.yml

@@ -13,14 +13,14 @@ jobs:
     if: github.event.pull_request.merged == true && github.event.pull_request.base.ref == 'main'
     runs-on: ubuntu-24.04
     steps:
+      - name: Checkout code
+        uses: actions/checkout@f43a0e5ff2bd294095638e18286ca9a3d1956744 # v3.6.0
+
       - name: Set up Go 1.24
         uses: actions/setup-go@d35c59abb061a4a6fb18e82ac0862c26744d6ab5 # v5.5.0
         with:
           go-version-file: go.mod
 
-      - name: Checkout code
-        uses: actions/checkout@f43a0e5ff2bd294095638e18286ca9a3d1956744 # v3.6.0
-
       - name: Login to Quay.io
         uses: docker/login-action@465a07811f14bebb1938fbed4728c6a1ff8901fc # v2.2.0
         with: