chore: only running e2e CI on the root canonical repo (#293)

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**Motivation:**
- Unblock external contributors

**Modifications:**

**Result:**
- CI only runs on canonical repo and main branch

**Testing:**

**Open questions:**

Author: bdchatham

.github/workflows/e2e.yml

@@ -17,6 +17,7 @@ env:
 jobs:
   e2e:
     runs-on: ubuntu-latest
+    if: github.repository == 'Layr-Labs/devkit-cli'
     steps:
       - name: Checkout repository
         uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2