extension_ci: Set fetch-depth to 0 in tests (#49996)

This makes the full history available in tests. 

Release Notes:

- N/A

.github/workflows/extension_tests.yml

@@ -87,7 +87,7 @@ jobs:
       uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683
       with:
         clean: false
-        fetch-depth: ${{ github.ref == 'refs/heads/main' && 2 || 350 }}
+        fetch-depth: 0
     - id: cache-zed-extension-cli
       name: extension_tests::cache_zed_extension_cli
       uses: actions/cache@0057852bfaa89a56745cba8c7296529d2fc39830