ci: fix generate-compat-db scarb version mismatch

The job checked out katana at ref v1.6.0, so it used the old version of
generate-test-db.sh which doesn't support --dojo-tag. This caused the
script to clone dojo from latest main (instead of v1.6.0), which
requires starknet ^2.13 — incompatible with scarb 2.10.1.

Fix by checking out main (no cargo build for katana in this job — it
uses the Docker image binary) so we get the current script that supports
--dojo-tag. Also remove the redundant separate dojo checkout since the
script handles cloning at the specified tag.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: kariy

.github/workflows/generate-db-dispatch.yml

@@ -13,20 +13,11 @@ jobs:
             ASDF_SOZO_VERSION: "1.7.0"
         steps:
             - uses: actions/checkout@v4
-              with:
-                  ref: v1.6.0
 
             # Workaround for https://github.com/actions/runner-images/issues/6775
             - run: git config --global --add safe.directory "*"
             - uses: Swatinem/rust-cache@v2
 
-            - name: Checkout Dojo repository
-              uses: actions/checkout@v4
-              with:
-                  repository: dojoengine/dojo
-                  ref: v1.6.0
-                  path: dojo
-
             - uses: software-mansion/setup-scarb@v1
               with:
                   scarb-version: "2.10.1"