extension_ci: Use larger runners for extension bundling (#45540)

`2x4` is not nearly enough for some of the grammars in use, hence change
this to a larger runner.

Also, reduce the size for the Rust runners a bit, as they don't need to
be quite as large for the amount of Rust code we have in extensions.

Release Notes:

- N/A

.github/workflows/extension_tests.yml

@@ -51,7 +51,7 @@ jobs:
     needs:
     - orchestrate
     if: needs.orchestrate.outputs.check_rust == 'true'
-    runs-on: namespace-profile-16x32-ubuntu-2204
+    runs-on: namespace-profile-4x8-ubuntu-2204
     steps:
     - name: steps::checkout_repo
       uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683
@@ -79,7 +79,7 @@ jobs:
     needs:
     - orchestrate
     if: needs.orchestrate.outputs.check_extension == 'true'
-    runs-on: namespace-profile-2x4-ubuntu-2404
+    runs-on: namespace-profile-8x32-ubuntu-2404
     steps:
     - name: steps::checkout_repo
       uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683